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SCERT AP Board 9th Class Social Solutions 8th Lesson Service Activities in India Textbook Questions and Answers.

AP State Syllabus 9th Class Social Studies Solutions 8th Lesson Service Activities in India

9th Class Social Studies 8th Lesson Service Activities in India Textbook Questions and Answers

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Question 1.
What is meant by the term “service activities”?
Answer:
1. Services rendered by different people in a specified activity are known as service activities.
E.g.: a) Teachers’ Services.
b) Health and Medical Services rendered by doctors and para-medical staff.
c) Services of people working in army, navy, and airforce.
d) Financial activities of banks and insurance companies.
e) Trading activities, etc.
All the above services can be termed as Service Activities.
2. Service activities do not produce any tangible commodity like paddy or cloth.
3. Service activities here refer to ‘the nature of work” done.
4. “Service activities” in this context of work does not mean something that is done “free of cost” or “out of love or devotion.”
5. All the above people earn money by rendering these “service activities.” This is their livelihood.
6. These service activities are required for agriculture and industrial activities.

Question 2.
List five service activities and give your reasons why they are not be considered as either agricultural or industrial activities.
Answer:
1. Health and Medical Services :
A doctor examines patients, prescribes medicines and monitors their progress. Other para-medical staff help doctors.

2. Trade :
Goods whether agriculture or manufacture goods are to be transported to distributors. Distributors in turn supply goods to wholesaler who in turn supplies them to retailers. And consumers purchase from the retailer. These are trading activities.

3) Financial Services :
Banks issue loans to all farmers and entrepreneurs and facilitate agriculture and industrial activities. Insurance companies insure goods against risk.

4) Defence :
Activities and people who work in all the armed forces like army, navy, and airforce.

5) Personal Services :
Workers who do domestic work, laundry, cleaning, dyeing, hair dressing, etc.

a) In all the above examples we can see that services are rendered.
b) Nothing new is produced here. In agriculture, we produce some crop and in industrial activity, we work upon raw materials and convert them into finished goods. Here in the above examples, nothing tangible is produced.
c) The above examples are special kind of activities that help agriculture and industry and also provide a lot of service that people require.
So we cannot consider the service activities as either agricultural or industrial activities.

Question 3.
How can service activities help in the overall development of a country?
Answer:

• Overall development of a country depends on developmental initiatives involving setting up of many establishments like educational institutions, hospitals, etc.
• Other developmental activities include provision of infrastructure facilities such as transportation, telecommunications, banks, insurance services, and other services like trading, book keeping, and public administration.
• All these activities are service activities that help agriculture and industry and facilitate overall development of our country.

Question 4.
How are agricultural and industrial activities related to services?
Answer:
Agricultural and industrial activities need the services of various sectors.

1. Transportation helps in assembling raw material from the mines to industrial spots and to carry finished goods from industry to markets.
2. Road and other services to transport finished products.
3. Marketing services.
4. Import and export services.
5. Storage services like godowns.
6. Financial services like banking loan and insurance services.
7. Health and education services.
8. Communication system, information technology.

Question 5.
‘The growth of service sector is sustainable and can make India as a rich country.’ Do you agree with this statement? Elaborate.
Answer:

• There is a lot of change in technology and by exporting our services i.e., “BPOs” or “Outsourcing” we are earning foreign exchange.
• Service Sector constitutes one-fourth of the jobs people do in India.
• 90.5 lakhs and 25.3 lakhs of people are involved in community, social, personal services, and transport and communications respectively.
• So many jobs are available for educated people in service sector.
• Due to the development of telecommunications and information technology, the world has become a global village.
• Due to the establishment of Multinational Companies, we are getting projects from foreign countries.
• The standard of living of the people has been increased for the last two decades. Hence the growth of service sector is sustainable and can make India a rich country.

Question 6.
Why are service sector activities becoming important?
Answer:

• Service sector activities include all the services like Banking and Finance, Trade and Commerce, Transport and Communications, Health, Education, Personal services, etc.
• Service sector activities do special kind of activities that help agriculture and industry and provide a lot of services that people require.
• Provision of education and health fulfils the aim of social welfare.
• Trade and commerce help in bringing buyers and sellers together.
• Transportation is necessary forthe movement of men and material from one place to another.
• The development of telecommunications has cut the geographical boundaries and helps in globalization.
• They provide information about new markets and products.
• They are considered as means of modernization.
• They provide employment opportunities and are very useful in rising the standard of living of the people.
  Due to the above reasons the service sector activities are becoming important.

Question 7.
Service activities cannot expand beyond a level unless agriculture and industries. Explain.
Answer:

• Development of a country is always measured on production of goods and services.
• Increase in production is possible only through the development of agriculture sector and industrial sector.
• Service activities are necessary to modernize agriculture and industrial sector.
• Development services without increase in production is a waste.
• Hence service activities cannot expand beyond a level unless agriculture and industries develop.
• In fact, all three sectors should go hand in hand.

Question 8.
How can service sector reduce educated unemployment in India?
Answer:

• There has been tremendous change in the communication technology which has opened a wide range of jobs for educated people.
• Business Process Outsourcing (BPO) has brought in new kinds of employment opportunities.
• They provide services to people located across the globe using telecommunication links.
• The entertainment industry creates jobs to work in various print media firms, cable television channels.
• We see number of internet cafes and telephone booths in most of the cities and towns.
• The advertising industry has also brought new job opportunities.
• Many new jobs are available in Banking and insurance sectors.
  Hence service sector can reduce educated unemployment in our country.

Question 9.
Is there any migration of labourers from your area? Find out the reasons for the migration.
Answer:
Yes, there is migration of labourers from our village.

Reasons for migration :

1. People migrate from rural areas mainly due to insufficient employment opportuni¬ties, inadequate income available in rural employment.
2. People also migrate with the expectation of higher incomes and more opportunities for family members and may be better services.
3. For some people from rural areas moving to cities and towns, to work in industry and other services activities have been recognised as a natural response to increase their income and for better family prospects.

Question 10.
Read the 9th paragraph of this chapter ‘Working people engaged’ and answer the following.

Working people engaged in service activities do not produce a commodity, like that in agriculture or in industry. They do special kind of activities that help agriculture and industry and also provide a lot of service that people require. Another example is the banking and finance related service activities required by people and business organisations. You have read about this in Class VIII chapter “Money and Banking”. Similarly there are the cell phone, internet and all other types of telecommunication service providers.

What are the service activities required for agriculture and industries?
Answer:

• Banks and other financial institutions finance the agriculture and industrial activities by lending of funds.
• Transportation services help in the development of the agriculture sector through effective distribution of food grains and perishable goods from the producing areas to the markets without interruption.
• Transportation helps in the distribution of raw material to the industrial units.
• Service sector activities provide information about new markets and products.
• A variety of trading activities like distributors, wholesalers and retailers also constitute a major segment of service activities.
• These activities help in bring buyers and sellers together.
• Proper power supply to various industrial units facilitates industrial growth.

Question 11.
Observe the map given in the (text) page 104. Locate the software technology parks of our country in the India outline map.
Answer:
Students Activity

Question 12.
Discuss with any seven people identify with sector they are employed in. Write a brief note or design a poster about their work. What relationship do you see between their employment and place of residence?

Name of the person	Nature of work done	Agriculture/Industry/Services

Explain your reason for the classification.
Answer:

Name of the person	Nature of work done	Agriculture/Industry/Services
“X”	Works in steel plant	Industry
“Y”	Carpenter	Services
“Z”	Landlord	Agriculture
“A”	Works in telephone exchange	Services
“B”	Teacher	Services
“C”	Goldsmith	Services
“D”	Works in the land of others	Agriculture
“E”	Match box making	Industry

1) Primary sector :
This includes those activities that are undertaken by directly using natural resources, e.g.: Cultivation of paddy. This is known as primary sector because it forms the base of subsequent products that are made from it. This sector is also called Agriculture and Related sector.

2) Secondary sector :
This sector covers those activities in which natural and primary products are changed into other forms through ways of manufacturing.
e.g.: manufacturing paper from bamboo. This sector is also known as industrial sector.

3) Tertiary sector :
This sector includes those activities that help in the development of the primary and secondary sectors, e.g.: railways. Since they provide services to help the production, this sector is also called service sector.

9th Class Social Studies 8th Lesson Service Activities in India InText Questions and Answers

Question 1.
There are eight categories of service activities given below. Some details are filled in, others are left out. Fill in the blank ones after discussing with your teacher. (Text Book Page No. 97 & 98)
Answer:
1. Education:
Institutions – schools, colleges, universities, technical institutions come under this category. This means those who are working in these institutions such as teachers, all the administrative staff and their activities constitute services.

2. Health and Medical Services :
Primary health centres. General hospitals. Old aae homes, etc.

3. Trade :
A variety of selling activities both wholesale and retail that we see around. National and International business, etc.

4. Public Administration :
Public services under village and town panchayats, state and central governments come under this category. Examples: people who work in police stations, workers of various other government departments such as village administrative officers, revenue inspectors, tehsildars, Collectors, those who work in all kinds of courts, assistants, clerks, accountants, typists, peons, drivers etc.

5. Defence :
Activities and people who work in all the armed forces like army, navy and air force.

6. Financial activities :
Banks and different saving schemes, postal, life insurance, etc.

7. Personal Services :
Workers who do domestic work, laundry, cleaning, dyeing services, hair dressing, running beauty parlours, tailoring shops, photo, and video studios.

8. Activities such as:
People working in entertainment and information technology industry – production of films, TV serials, those working in media, newspapers, television channels, and advertisement agencies are also included in services.

Question 2.
What do you think about Foreign Direct investment {FDI} in Retailing Activities? Can government do anything to address this issue? (Text Book Page No. 101)

• In my opinion, there will be gainers and losers from FDI in retail.
• Overall gains will outweigh to losses.
• In course of time the losess too will benefit.
• It was opined that large and medium sized farmers will initially benefit the most, while the small farmers or landless labour will be the losers.
• However, the purchases by the big super markets will increase demand for agricultural products, which in turn will expand agricultural out put, and increase demand for labour.
• This will increase agricultural wages in the long run.

To set right this issue, the government has to take following steps.

1. Best storage facilities also should be provided by the govt.
2. Govt should take measures that market will not go in the hands of few people.
3. Govt must keep Foreign Direct Investment under its control.

Question 3.
Who, in your opinion should set up new medical institutions – privatesectoror government? Why? (Text Book Page No. 102)
Answer:
The following organizations shall be eligible to apply for permission to set up a medical college.

1. A state govt. / union territory.
2. A university
3. An autonomous body promoted by central and state governments.
4. A society registered under the Societies Registation Act, 1860.
5. A public religious or charitable trust registered under the Trust Act, 1882.
6. Companies registered under Company Act.

I think that the government should set up new medical institutions.

Reason:
Because it is not easy to any private sector persons to satisfy the norms of the Medical Counsil of India.

Question 4.
The following table shows the number of workers (in lakhs) employed in different service activities in large enterprises in 1991 and 2010. Read the table carefully and answer the questions that follow. (Text Book Page No. 100)

a) Which service activity gave maximum employment in 2010?
Answer:
Community, social and personal services gave maximum employment.

b) Has the number of government jobs increased or decreased over the years?
Answer:
The number of government jobs has been drecreased from 136 lakhs in 1991 to 131.6 lakhs in 2010.

c) What kind of jobs has government generated the most during this period?
Answer:
The jobs in finance, insurance, and real estate have been increased from 11.9 lakhs to 14.1 lakhs for the last 20 years.

d) What kind of jobs were people able to get in the private service activities?
Answer:
People were able to get private jobs in all service sector activities like trading, transportation, finance and personal services.

e) Are there any differences between jobs provided by the government and private employers? Discuss.
Answer:
a) The number of job opportunities in the private sector has been increased from 20.9 lakhs in 1991 to 43.7 lakhs in 2010.
b) The salaries of the private jobs are good but the employees are expected to work very long hours.
c) Government jobs have security whereas private jobs do not give any security to their employees.

Question 5.
Talk to some retail shop owners in your neighbourhood. Discuss their opinions on foreign retailing shops in your class. (Text Book Page No. 102)
Owner of shop – 1 : “Traders and kirana store owners are not fully prepared to face foreign retailers.”
Owne^sfiop – 2’/ “6ur shops are safe. Our customers will not visit those shops.”
Owner of shop – 3 : “The customer will get the knowledge of quality of the provisions. Those shops are maintaining least quality things.”
– We discussed all these points in the classroom.

Question 6.
What is your opinion on foreign companies setting up retail shops in India? How do you think that they generate employment in India? (Text Book Page No. 102)
Answer:

• Foreign direct investment will definetly help the farmers in long run.
• It is argued that there will be loss of jobs in traditional, smaller retail sector.
• However, the purchases by the big supermarkets will increase demand for agricultural products, which in turn will expand agricultural output, which in turn may increase demand for labour.
• This will increase wages in the long run.

Question 7.
Prepare a table with two columns and list out the advantages and disadvantages of allowing foreign company retail stores in India. (Text Book Page No. 102)
Answer:

Advantages	Disadvantages
1. Foreign direct investment will increase demand for farm products.	1. The small farmers and landless labour will be the losers.
2. Basing on demand the production of farm goods will be increased.	2. FDIs will influence the farmers and may buy produce at low costs.
3. Better storage facilities will be provided.	3. They will not invest much on storage facilities but charge high rates for storage.
4. Better storage facilities will minimise waste of farm produce.	4. There will be loss of jobs in traditional and small retail sectors.
5. Farmers will be saved from the traps of moneylenders.	5. The foreign companies will sooner or later misuse – their power to buy in large quantities.

Question 8.
Why is it necessary to establish more medical institutions in India? (Text Book Page No. 102)
Answer:

• The government of India recognizes ‘Health for all’ as a national goal.
• The medical education and health care in India are facing serious challenges in content and competencies.
• There is a need to balance for more medical colleges with the maintenance and improvement of quality standards.
• There are disparities between different states and rural/urban areas with regard to access to basic medical services and quality health care.
  To overcome all these problems, it is necessary to establish more medical institutions in India.

 

SCERT AP Board 9th Class Social Solutions 7th Lesson Industries in India Textbook Questions and Answers.

AP State Syllabus 9th Class Social Studies Solutions 7th Lesson Industries in India

9th Class Social Studies 7th Lesson Industries in India Textbook Questions and Answers

Improve Your Learning

Question 1.
Why government took up the responsibility to set up basic goods industries?
Answer:

• Basic industries produce essential goods that can form a base to support a large variety of factories.
• Huge amount of capital is required to set up basic goods industries.
• Moreover it takes a long time to set up basic industries.
  E.g.: For setting up a power plant for production of electricity, it would require five to ten years.
• Private industrial groups were not willing to invest in such industries.
• Hence the Government took up the responsibility to set up basic goods industries.

Question 2.
Why are industries located in specific areas?
Answer:

• All factories need raw materials from which goods can be produced.
• Transportation is needed to bring raw materials to factories and transfer finished goods from them.
• So industries are located in specific areas where raw materials like minerals are available.
• Industries are also concentrated where infrastructural facilities like transportation electricity, banking services, etc. are available.

Question 3.
What are the basic goods industries? How they are different from consumer goods industries?
Answer:

Basic Goods Industries	Consumer Goods Industries
1. Factories producing essential goods necessary for industries are called basic goods industries. E.g.: Machines, electricity, etc.	1. Factories producing goods which for direct consumption are called consumer goods. E.g.: Soaps, Furniture, TVs, etc.
2. These goods are not for direct consumption.	2. These goods are directly consumed by consumers.
3. Basic industries produce essential goods that can farm a base to support a large variety of factories.	3. Consumer goods industries did not support any other industries.

Question 4.
Give a list of towns/areas in which some conventional mineral resources are found and ask students to identify then possible industries which can be set up.

Minerals/ Resources	Towns/areas in which these resources are available	List the kind of industries that can be set up in this area
1. Iron ore
2. Coal
3. Jute
4. Oil
5. Natural Gas
6. Forests
7. Manganese
8. Bauxite

Answer:

Minerals/ Resources	Towns/areas in which these resources are available	List the kind of industries that can be set up in this area
1. Iron ore	1. Singhbhum in Jarkhand 2. Mayurbhanj, Koenjhar in Odisha 3. Raipur and Bastar in Chattisgarh. 4. Bellary and Chikmaglur in Karnataka. 5. Salem in Tamilnadu 6. Khammam in Telangana and Rayalaseema in Andhra Pradesh. 7. Ratnagiri and Chanda in Maharashtra.	1. Iron and steel industry 2. Heavy machines 3. Tools 4. Weapons 5. Constructions and transport vehicles, etc. 6. Railway coaches, etc.
2. Coal	Important coal fields are 1. Jharia, Chandrapura, Bokaro and Giridhi in Jarkhand. 2. Ranigunj and Asansal in West Bengal. 3. Singrauli and Korba in Madhya Pradesh. 4. Singareni in Telangana	1. Iron and steel industry 2. Thermal power industry 3. Used as fuel in so many other industries. 4. Largely used in railways.
3. Jute	West Bengal, Assom, Bihar and Odisha.	Jute industry is concentrated in West Bengal. 1. Jute textiles 2. Bag making 3. Carpet making 4. Door mats, etc.
4. Oil	Gujarat, Assom, Bombay High	Different types of industries.
5. Natural Gas	1. Cambay and Ankleshwar fields in Gujarat 2. Bombay High in Maharashtra.	Power industry Fertilizer industry Used as fuel
6. Forests	Forests are found in Madhya Pradesh, Telangana, Andhra Pradesh, Odisha, Maharashtra, Arunachal Pradesh and Uttar Pradesh.	Forests yield both softwood and hard wood. Forest based industries are- 1. Paper (softwood trees) 2. Furniture 3. Timber 4. Soaps 5. Match boxes 6. Handicraft 7. Turpentine and 8. Railway sleepers
7. Manganese	1. Koenjhar, kalahandi, Mayurbhanj Sundarghar and Thalcher in Odisha. 2. Chitradurg, Shimoga, Chikmanglore, Bellary and Dharwad in Karnataka. 3. Bhalghat, Seori, Jabalpur in Madhya Pradesh. 4. Singhbum in Jarkhand. 5. Panchamahal in Gujarat. 6. Srikakulam and Visakhapatnam districts in Andhra Pradesh.	1. Iron and steel industry 2. Chemical industry 3. Bleaching powder 4. Electrical 5. Glass 6. Leather 7. Photography and 8. Metal industry
8. Bauxite	1. Palmau, Ranchi, Monghyr and Shahabad in Jarkhand. 2. Balaghat, Jabalpur, Bilaspur and Rajgarh in Madhya Pradesh. 3. Amreli and Kutch in Gujarat. 4. Belgaum in Karnataka. 5. Madurai, Nilgiris and Coimbatore in Tamilnadu. 6. Visakhapatnam in Andhra Pradesh	Used in Aluminium making which in turn used in aircraft, automobiles, ships, utensils, railways, photographic material and electrical goods industry.

Question 5.
Why government in 1990s allowed private industries in many areas which were earlier restricted only to government?
Answer:

• Indian industry as a result of government’s control was not modernizing fast and was producing goods at high cost and not making technological improvement.
• Government used to allocate a specifc amount every year to operate these industries.
• It was expected that these industries become independent, generate revenue for the government.
• But these government run factories continually require government assistance.
• Their functioning was much below that was expected.
• So, in the 1990s a new industrial policy was announced. Many activities which were earlier restricted only for the government are now allowed for the private industries.

Question 6.
What is the impact of industrial development on employment generation?
Answer:

• An important goal of industrial policies in India was to generate employment opportunities in industrial activities.
• Raising the proportion of people employed in factories is also generally seen as an important indicator of economic development of a country.
• Today nearly 2 lakh large factories and 3 crore small manufacturing units are operating in India.
• These units employ nearly about one-fifth of India’s 460 million workers.
• Number of employees generated in industrial section has increased from 11% in 1972-73 to 22 % in 2009-10.
• But large industries began to replace workers with technology. More and more automation has taken place.
• This has led to almost zero additional employment in large factrories.

Question 7.
What is the impact of industrial development on revenue?
Answer:

• When goods made in factories and exported to other countries, we get revenue.
• A few decades before, three-fourths of income from goods exported from manufacturing industries alone.
• Even today, nearly two-third of goods exports is contributed by industries and particularly small industries.
• Factory goods exported range from gems, jewellery, chemicals, cars, machinery, cashewnuts, etc.
• The money or foreign exchange earned in this process enable us to import from other countries a large number of goods that we want from other countries.

Question 8.
“Industrial activities increase environmental problems” Discuss.
Answer:

• The production process in industries involves the use of electricity and application of different chemicals.
• In the course of production, these industries release a lot of other materials. They are causing pollution in the industrial locations.
• The industrialization led to the indiscriminate exploitation of minerals, forests, soils, air, etc.
• It leads to deforestation and damages the natural habitat of animals.
• Underground water is being contaminated due to the release of wastes by the industries.
• Some animals are endangered and some creatures have become extinct.
• The depletion of ozone layer, pollution of water, air, soil has increased ecological problems.

Question 9.
Write a few slogans on the prevention of environment pollution.
Answer:

• We were born to help the world, not to destroy it.
• Only when the last tree has died, the last river has been poisoned and the last fish has been caught, will we realize that we cannot eat money?
• Save the environment and you will save the life and future.
• Hungry and the Earth will serve, Thirst and the seas will water I Do you still want to cut that all?
• Man made global warming, the biggest scan in the history of mankind to fulfil his greediness? Understood this or nature will teach you.
• Stop pollution – Stop global warming.

Question 10.
Read the para 3 of page 83 and comment on it.

The electronics industrys covers a wide range of products from transistor sets to television, telephones, cellular telecom, pagers, telephone exchange, radars, computers and many other equipments required by the telecommunication industry. Bengaluru has emerged as the electronic capital of India. Other important centres for electronic goods are Mumbai, Delhi, Hyderabad, Pune, Chennai, Kolkata, Lucknow and Coimbatore. 18 software technology parks provide single window service and high data communication facility to software experts. A major impact of this industry has been on employment generation. Upto 31 March 2005, the IT industry employed over one million persons. This number is expected to increase eight-fold in the next 3 to 4 years. It is encouraging to know that 30 per cent of the people employed in this sector are women. This industry has been a major foreign exchange earner in the last two or three years ‘ because of its fast growing Business Processes Outsourcing (BPO) sector. The continuing growth in the hardware and software is the key to the success of IT industry in India.

Answer:
IT and electronics are the fast growing segments of Indian industry both in terms of production and exports. This sector is attracting considerable interest not only as a vast market but also as potential production base international companies.

In recent times, software development and IT enabled services have emerged as a niche opportunity for India in the global context.

The Government is taking all necessary steps to make India, a Global IT super power and a front runner in the age of information revolution. It earns a major share of foreign exchange.

Question 11.
Observe the map given on page 95 and locate the iron and steel plants in the India outline map.

Answer:

Question 12.
Select one agro-based and one mineral based industry in your area.
i) What are the raw materials they use?
ii) What are the other inputs in the process of manufacturing that involve transportation cost?
iii) Are these factories following environmental norms?
Answer:
1. Agro Based :
Nandini Foods.

2. Mineral Based :
Ramagundam Thermal Power Station

Agro Based	Mineral Based
1. Raw material: Sugar, powders, chillies, tamarind, oil, etc.	Coal, etc.
2. Inputs that involve transportation lost: raw materials, staff and finished goods to market.	Raw materials, staff
3. Environmental Norms : Yes, upto some extent	Yes, but the wastage is sent out into a canal.

9th Class Social Studies 7th Lesson Industries in India InText Questions and Answers

Question 1.
Can you make a list of products produced by factories for other factories? (Text Book Page No. 76)
Answer:

1. Moulds
2. Speakers
3. Spare parts
4. Tyres, Tubes, etc.

Question 2.
Have you seen machines used in a factory? Make a collage of different kinds of machines that are used. (Text Book Page No. 76)
Answer:
I have seen a welding factory.
Machines in the factory are :

1. arc welding
2. resistance welding
3. laser welding
4. electron bean welding
5. stud welding
6. orbital welding
7. wave soldering
8. hot dip brazing
9. torch brazing
10. indution brazing
11. ultrasonic
12. friction welding

Question 3.
Discuss what is meant by the word “basic”. What are the basic necessities for industries? (Text Book Page No. 76)
Answer:

• “Basic” means the things that are basically necessary.
• The basic necessities for setting up any industries are machines, electricity, minerals and ores and infrastructural facilities like transport, telephones, etc.

Question 4.
At the time of independence what were the objectives that were desired to be achieved through industrialization? (Text Book Page No. 76)
Answer:

• After 1947, India began many initiatives to promote industrial activities in the country.
• Major objectives were – to become self-sufficient in meeting our needs and to make the country an industrially developed nation.

Question 5.
Where should the sugar and jaggery mills be ideally located? (Text Book Page No. 80)
Answer:
The sugar and jaggery mills should be ideally located near the crop grown areas.

Question 6.
Where would it be economically viable to set up the cement manufacturing units? (Text Book Page No. 82)
Answer:
Cement manufacturing units can be established near the areas where the raw materials are available in bulk.
Raw materials : Limestone, silica, alumina, gypsum, coal and electric power and transportation facilities.

Question 7.
Can you point out some examples of increase in production of goods that are used in the production of many products by different factories? (Text Book Page No. 90)
Answer:

1. Steel
2. Engines
3. Cement
4. Bricks
5. Wood
6. Glass
7. Vegetables
8. Cotton, etc.

Question 8.
The industry has strategically located plants in Gujarat that have suitable access to the market in the Gulf countries. Find out where the plants are located in other states of India. Find their names. (Text Book Page No. 82)
Answer:

1. Nirman Cements Ltd – Bihar.
2. Grasim Cements Ltd – Madhya Pradesh
3. Sagar Cements – Telangana
4. The India Cements Ltd – Tamilnadu

Question 9.
Fill in the following table. For some industries, you may need to discuss with the teacher. (Text Book Page No. 84)

Industry	States in which they are currently concentrated	Why they are concentrated in those states?
Chemical Industry
Fertiliser Industry
Cement Industry
Automobiles Industry

Answer:

Industry	States in which they are currently concentrated	Why they are concentrated in those states?
Chemical Industry	Gujarat	Availability of raw material, skilled and unskilled labourers, electricity, water, financial assistance, transport facilities, etc.
Fertiliser Industry	Maharashtra
Cement Industry	Rajasthan, Telangana, A.P., M.P, Gujarat
Automobiles Industry	Tamilnadu

Question 10.
Observe the following pie charts. (Text Book Page No. 87, 88)

a) What are the differences in employment in the three kinds of economic activities that you notice from these pie charts?
Answer:

• The employment generation in agricultural sector has been decreased from 74% in 1972-73 to 53% in 2009-10.
• The employment generation in industrial sector has been increased from 11% in 1972-73 to 22% in 2009-10.
• The employment generation in service sector has shown an increase of 10%.

b) What is the percentage of change in employment by industry?
Answer:
There is a 11% increase in employment generated by industry.

c) Did we expect to see a greater change in employment by industry that did not happen?
Answer:
1) Yes, we expected a greater change in employment by industry. But it did not happen.
2) Large industries began to replace workers with technology. More and more automation has taken place.
3) Hence it did not happen.

Question 11.
Look at the following Graph and answer the following question. (Text Book Page No. 89)

What has been the increase in production of cloth over the past 30 years? What would be the impact of this? Discuss in your class. (Text Book Page No. 90)
Answer:
1. The production of cotton cloth was 8000 million square metres approximately in 1980-81. The production went up to 15000 million square metres by 1990-91, to 19000 million square metres by 2000-01. The production has been increased to 31000 million square metres approximately by 2010-11.

2. The production of other cloth material was approximately 2500 million square metres in 1980-81 and that went up to 7000 million square metres by 1990-91, to 20000 million square metres by 2000-01 and to 30000 million square metres approximately
by 2010-11.

Question 12.
Refer the chart that shows the production of cement and steel construct a table to show the increase from 80-81 to present times. Discuss some positive and negative effect of this increase in production. (Text Book Page No. 90)

Answer:

The positive and negative effects of the increase in production :
1. The increase in the production of cement has positive impact on the development of our country. The infrastructural facilities like buildings, dams, roads etc., are increased due to the increase of production of cement.

2. Negative impact of cement production: The heating of limestone and clay may release mercury into the air which affects the health of the people and pollutes the ground water too.

Steel Production:
1. The increase in the production of steei has impact on the production of other goods, iike heavy tools and machines etc.

2. The steel factories release poisonous gases into the atmosphere and release waste into the streams causing air and water pollution.

Question 13.
Iron is the basic requirement for a large number of goods produced by various factories. Explain this with examples that you see around. (Text Book Page No. 76)
Answer:

• Iron is used in making steel, machinery, tools and weapons.
• Iron is also used in shipbuilding industry.
• Iron is also used for many other purposes in constructions and transport.

Question 14.
Make a chart to show how petroleum is the basic requirement for a large number of products. (Text Book Page No. 76)
Answer:
Petroleum or crude oil is a naturally occurring liquid found in the earth. It is refined and used to make so many products. The byproducts are Petrol, Diesel, Kerosene, etc.
It is used in:

1. Petrochemical industry
2. Plastic making
3. Lubricating oils
4. Fertilizers
5. Asphalt – which is used in road construction
6. Pesticides
7. Detergents
8. Photographic film
9. Artificial fibres, etc.

Question 15.
Why is the per capita consumption of steel so low in India? (Text Book Page No. 81)
Answer:

• India is the developing country, the process of development is a little bit slow than other developed countries.
• Economy plays a vital role in the development of India economy is good but not best.
• The steel industry has limited factories in our country.
• The production is also limited. So the per capita consumption of steel is low in India.

Question 16.
Why did Mahatma Gandhi lay emphasis on spinning yarn and weaving khadi? (Text Book Page No. 79)
Answer:

• To spend time usefully with some other work,
• To fight against foreign cloths imported,
• To encourage village industries,
• To insist that everyone learn to do his own work like making the yarn for his cloth and
• To lead a simple life and minimising the needs for living.

9th Class Social Studies 7th Lesson Industries in India Activity

Collect the wrappers of a tea packets and tooth paste. Read the wrappers carefully and try to relate to the question below. (Text Book Page No. 77)
Answer:
Student’s Activity

…………..(1)………….. can be considered as a product of agro based industry. …………..(2)………….. can be considered a product of mineral based industry.
Answer:
1) Tea,
2) Toothpaste

Raw material for the tooth paste…………..(1)………….. and …………..(2)…………..
industry. That industry is called key or basic industry. Whereas the tooth paste is a consumer goods and the industry producing such goods is called consumer goods industry.
Answer:
1) Flouride,
2) Calcium

The ownership of industries could be lying with individuals or groups of individuals such as …………..(1)………….. (for the tea packets) and …………..(2)………….. (tooth paste). Such an industry is called a private sector industry whereas if the ownership belongs to the government, it will be called as public sector industry. Two examples of public sector industries are …………..(3)………….. and …………..(4)…………..
Answer:
1) Brookebond,
2) Dabur (Red),
3) Bharat Dynamics Ltd,
4) BHEL Ltd.

Some industries are also owned by large number of people who supply raw materials (milk/sugarcane) or supply their labour (coir) pool their resources to run them. Such industries are called cooperative industries.

SCERT AP Board 9th Class Social Solutions 6th Lesson Agriculture in India Textbook Questions and Answers.

AP State Syllabus 9th Class Social Studies Solutions 6th Lesson Agriculture in India

9th Class Social Studies 6th Lesson Agriculture in India Textbook Questions and Answers

Improve Your Learning

Question 1.
Name one important beverage crop and specify the geographical conditions required for its growth.
Answer:

• Tea is an important beverage crop.
• The tea plant grows well in tropical and sub-tropical climates.
• Fertile, well-drained soil, rich in humus and organic matter is essential.
• Tea bushes require warm and moist frost-free climate all through the year.
• Frequent showers are necessary.

Question 2.
The land under cultivation has got reduced day by day. Can you imagine its consequences?
Answer:

• The land under cultivation has been reducing due to the competition for land between non-agricultural uses such as housing, etc.
• As a result, the productivity of India has started showing a declining trend.
• That would lead to the scarcity of food grains in future and in turn poverty and drought situation would prevail in our country.

Question 3.
On an outline map of India show millet producing areas.
Answer:

Question 4.
What is a Minimum Support Price (MSP)? Why is a MSP needed?
Answer:
1) A Minimum Support Price is a price at which the farmers can sell their grain, if they want, to the Government.
2) The Government sets the MSP so as to cover the cost of cultivation and allow a little bit of profit to the farmer.
3) Thus the farmer, produced far markets within the country.
4) The farmers are not forced to sell their grains at cheaper prices to the traders.

Question 5.
Explain all the ways the Indian government supported the Green Revolution.
Answer:

• The Green Revolution was initially introduced in Punjab, Haryana, western Uttar Pradesh, and in some parts of Andhra Pradesh and Tamilnadu.
• The Government introduced new kinds of seeds, known as High Yielding Varieties to the Indian soils.
• It was also accompanied by use of chemical fertilizers, machinery such as tractors, and others besides irrigation facilities.
• A variety of cooperative banks were set up to provide credit to farmers so that they buy raw materials such as seeds, fertilizers, and pesticides, machinery required for modern farming.

Question 6.
Do you think it is important for India to be self-sufficient in food grain production? Discuss.
Answer:

• A large portion of our population especially children and poor communities are unable to get adequate nutrition.
• Whenever there were little rains, drought situations prevailed. This led to decrease in food production and forced government to import food grains.
• To avoid these kind of situations we should be self-sufficient in food grain production.
• A large stock of food grains has built-up with the government through Food
  Corporation of India that could be used in case of shortage and can avoid drought and famine situations in our country.

Question 7.
How is dry land agriculture different from agriculture in other areas?
Answer:

• 45% of the cultivable land which cannot easily be irrigated and depend solely on rainfall is known as dryland in our country.
• Unlike the cultivation of irrigated lands, dryland farming poses different challenges.
  a) Conserving rainfall that the area receives is the first step. This is done through watershed development programme which includes afforestation, bunding, building check-dams, and tanks.
  b) Fertility of the soil needs to be raised by adding organic manure.
  c) Farmers may also need new varieties of seeds suitable for different regions, knowledge about the best ways of growing a mix of crops on the same land etc.
  Hence farming in dryland is different from other areas.

Question 8.
Can you recall the incidents such as pesticides being found in soft drinks? How is this related to the use of pesticides? Discuss.
Answer:

• The use of pesticides is polluting underground water.
• The soft drink factories use this underground water for making soft drinks.
• Hence undissolved pesticides are seen in soft drink.

Question 9.
Why is chemical fertilizer used in new farming methods? How could use of fertilizers make soil less fertile ? What are the alternative ways of enriching soil?
Answer:

• The chemical fertilizers are used to increase production of crops.
• But the chemical fertilizers are basically made for petro-chemicals. And eventually remain in the soil.
• As a result, many micro organisms like earth worms are destroyed.
• These micro organisms increase the fertlity of the soil. But these are detroyed and hence this, in turn, affects the long run fertility of the soil.
• The alternative ways of enriching soil, like vermicompost, can be used to increase the fertility of the soil.

Question 10.
How has the Green Revolution in some areas resulted in short-term gains but longterm losses to farmers?
Answer:

• In Green Revoluton, the farmers are encouraged to pump ground water to water-intensive crops in low rainfall areas.
• This unsustainable pumping has reduced water storage in ground.
• Consequently, many wells and tubewells have run dry.
• More over the use of chemical fertilizers has also affected the long-term fertility of the soil. Hence we can say that Green Revolution has short-term gains and long term losses.

Question 11.
What could be the effects of foreign trade on farmers’ income?
Answer:

• Foreign trade could cause farmers’ income to fluctuate a lot.
• In certain years and for certain crops the farmers might gain from exports.
• In other years, farmers could lose because of cheap imports and fall in prices of farm products.
• Small farmers without much savings will not be able to bear this loss.
• They will be caught in debt trap and become poorer.
• Hence the government must be careful in allowing trade in farm products.

Question 12.
In earlier classes we have studied about land distribution. How does the following image reflect this idea? Write a paragraph about this in the context of Indian agriculture.

Answer:
In India more than 70% of the farmers are having only small and marginal holdings,
i. e., Less than 2 hectares and hence most of these farms are not viable. The small farmers cannot produce enough to meet even their basic requirements of their families. They can invest more in agriculture to increase production. They are unable to get financial assistances.
Caption : “A man of sixty acres :
A group of six feet”.

Question 13.
Read the para under the title ‘Fertilizer Problems’ on page 70 and comment on it.

Fertilizer Problems : Manure and compost contain humus and living organisms that slowly release minerals as they decompose. Chemical fertilizers provide minerals (usually nitrogen, phosphorus and potassium) which dissolve in water and are immediately available to plants, but may not be retained in the soil for long. They may be leached from the soil and pollute groundwater, rivers, and lakes. Chemical fertilizers (as well as pesticides) can also kill bacteria and other organisms in the soil. This means that some time after their use, the soil will be less fertile than ever before. Without micro-organisms, the soil will be dependent on frequent addition of more and more chemical fertilizers. The variety of nutrients which are normally produced by micro-organisms may also be reduced. Thus, in many areas, the Green Revolution has actually resulted in a loss of soil fertility and ever-increasing costs to farmers.

Answer:

• The main environmental problem associated with fertilizer use is contamination of water with nitrates and phosphates.
• Elevated nitrogen levels in drinking water.
• Environmental pollution is a significant problem. But while most of the focus is placed on polluting industries, toxins like mercury and small particle traffic pollution, a major source of environmental devastation is caused by modern food production. Far from being life sustaining, our modern chemical dependent farming methods.

– Strip soil of nutrients
– Destroy critical soil microbes.
– Contribute to desertification and global climate change, and
– Saturate form lands with toxic pesticides, herbicides and fertilizers that then migrate into ground water, rivers, lakes and oceans.

Question 14.
Observe the map given in the page 74 and locate the States where paddy is grown in the India outline map.

Answer:

1. Punjab
2. Haryana
3. Uttar Pradesh
4. Bihar
5. West Bengal
6. Chattisgarh
7. Odisha
8. Telangana
9. Andhra Pradesh
10. Karnataka
11. Tamilnadu

Question 15.
Which crops are grown in your area? Which of these are grown from HYV seeds and which ones are grown from traditional seeds? Compare the HYV seeds and the traditional seeds with regard to each of the following points :
a) duration of crop
b) number of times irrigated
c) production
d) fertilisers
e) diseases
f) pesticides
Answer:
1. Paddy, sugarcane, maize, pulses are grown in our area.
2. Paddy is grown from HYV seeds and the remaining are grown from traditional seeds.
3.

	HYV Seeds	Traditional Seeds
Duration of crop	Less	More
No. of times irrigated	Least	More
Production (comparatively)	More	Less
Fertilisers	Nominal quantity	Large quantity
Diseases	Least chancess	More chances
Pesticides	Right quantity	More quantity

Question 16.
Conduct a Debate : Make the students two teams. One team should support chemical fertilizers and another should support organic farming.
Answer:
Teacher conducts this Debate.
Example : In agriculture it is better to be followed organic fertilizers.
Reasons :
Pesticides can enter the human body.
There is a chance of groundwater damage.
The use of fertilizers can reduce the natural nutrients on the soil surface, etc.

9th Class Social Studies 6th Lesson Agriculture in India InText Questions and Answers

Question 1.
Name some of the states of India where such farming is practised? (Text Book Page No. 59)
Answer:
Punjab, Haryana, Odisha, Karnataka, Telangana, Andhra Pradesh, Madhya Pradesh, Uttar
Pradesh and some parts of Rajasthan.

Question 2.
Give some more examples of crops which may be commercial in one region and may provide subsistence in another region. (Text Book Page No. 60)
Answer:
1) In Haryana and Punjab, rice is a commercial crop whereas in Odisha it is a subsistence crop.
2) In Punjab, maize is a commercial crop whereas in Jharkhand it is a subsistence crop.

Question 3.
Distinguish which of these pulses are grown in the kharif season and which are grown in the rabi season? (Text Book Page No. 62)
Answer:
Pulses grown in the Kharif season :
Red gram, Black gram and Green gram.

Pulses grown in Rabi season :
Peas, Bean, Chickling vetch and Lentil.

Question 4.
Complete the bar diagram given on P.65 in Textbook and find out the percentage of cultivators and agricultural labourers in 1971 and 2001 respectively. (Text Book Page No. 65)
Answer:

1. Student’s activity.
2. Percentage of cultivators in 1971 = 62
3. Percentage of agricultural labourers in 2001 = 46

Question 5.
In which decades the food grains yields grow fast? What could be probable reasons for this? (Text Book Page No. 69)
Answer:
The food grains yields grew fast between 1980 – 1990, 2000 – 2010.
The green revolution helped farmers to produce higher level of food grains.

Question 6.
Can organic farming produce enough food for all? (Text Book Page No. 72)
Answer:
If some measures are taken, I think, organic farming can produce food for all.

Question 7.
How is organic farming especially suited for small and marginal farmers? Discuss. (Text Book Page No. 72)
Answer:
Large sections of farmers in India and their land holdings are small and marginal.
Their access to external inputs is limited and their ability to improve production is low. Globalisation and the opening up of the trade barriers among the nations have resulted in the decline of agricultural prices in the local markets to the detriment of the interests of these small and marginal farmers. Thus organic farming especially is suited for small and marginal farmers.

Question 8.
Read the following table. (Text Book Page No. 66)
Number of farmers and land they possess in India (2010 – 2011)

Complete the data in the table and the explanation in the following passage below.
Majority of farmers operate only small plots of lands. A typical Indian marginal farmer has only aboutacres to cultivate. There are 924 lakh farmers so that ..(2)..% of all farmers are marginal. If we add up the number of small and marginal farmers they form …(3)..% of all farmers. However, even though in percentage terms medium and large farmers is small, the number in absolute terms is large. ..(4)…lakh farmers can be together considered to be in this group. They have a powerful voice in rural areas. This group of large and medium farmers together operate …(5)…% of the land. Each large farmer for example on an average operates ..(6)..acres of land. Compare this with each marginal farmer who operates on an average ..(7)..acres of land. This inequality in distribution of land explains the inequalities in opportunities that they experience, the pov¬erty or growth opportunity that they face.
Answer:

1. 2.5
2. 67%
3. 85%
4. 69
5. 32%
6. 42.9 acres
7. 0.95 acres.

Question 9.
Discuss the differences between self employment and looking for work using examples from your region. (Text Book Page No. 65)
Answer:
1. In self employment, people create their own employment and earn their livelihood. They do not depend either on government or an any other persons for their livelihood.
e.g.: Working in their own farms, opening a shop or public telephone booth or establishing a small organization like manufacturing of candles, matchboxes, etc.

2. On the other hand, some people cannot create their own employment. They generally depend either on government or on any other organization or a person for earning their livelihood.
e.g.: Working in the fields or others, or in a shop or working as government servant, etc.

Question 10.
Do you think that some families who were earlier cultivators are becoming agricultural labourers now? Discuss. (Text Book Page No. 65)
Answer:
Reasons:

1. Small land holdings
2. Dependency on seasons for rainfall
3. High rate of interests on loans
4. Very low minimum support price
5. Lack of technology
6. Big families and
7. Some rituals.
   All these changed the cultivators as agricultural labourers.

Question 11.
In which areas were the new methods of agriculture first tried? Why was the whole country not covered? (Text Book Page No. 68)
Answer:
1. The new methods were initially implemented in Punjab, Haryana, western Uttar Pradesh and in some districts of Telangana, Andhra Pradesh and Tamilnadu.

2. The HYV seeds required a lot of water and these areas were already irrigated.
Hence the new methods were introduced in these areas.

Question 12.
Why are different methods necessary for dry land areas? (Text Book Page No. 68)
Answer:

• 45% of the land which cannot be irrigated are known as dry lands.
• It would be very difficult and expensive to irrigate these dry lands.
• These areas must depend solely on rainfall.
  Hence different methods are necessary for dry land areas.

Question 13.
How increase in buffer stock would help to avoid situations of drought and famines? (Text Book Page No. 69)
Answer:

• A large stock of food grains should be maintained with the government.
• That buffer stock could be used in case of shortage of food grains and can also be used to supply foodgrains to inaccessible areas.
• We can also avoid drought and famine like situations in our country.

Question 14.
How farmers were able to raise higher amount of food grains on the same plot of land over the years? (Text Book Page No. 69)
Answer:
The use of High Yielding Varieties of seeds, chemical fertilizers, machinery, etc. made the farmers to raise higher amount of food grains on the same plot of land over the years.

Question 15.
Why did not the Indian government allow farmers to export foodgrains during the Green Revolution years? (Text Book Page No. 71)
Answer:
There would be a shortage of food grains if the government allows farmers to export food grains. So the government did not allow farmers to export food grains.

Question 16.
Why should government ban exports /import ? How does this policy help Indian farmers? (Text Book Page No. 71)
Answer:
Foreign trade could cause farmers income to fluctuate a lot. In some years farmers could lose because of cheap imports and fall in prices of farm products. So the exports ad imports should be banned.

Small farmers will not be able to bear this loss. They will get caught in debt trap and become poorer. So this ban helps the Indian farmers in preventing them from debts and heavy losses.

Question 17.
Use an atlas of India to find the locations of the below mentioned dams and mark them on a map of India. Also label the names of the major rivers on which these dams were built. (Text Book Page No. 67)
Answer:

1. Bhakra-Nangal Project (Punjab)
2. Nagarjuna Sagar Project (Telangana & Andhra Pradesh)
3. Hirakund Project (Odisha)
4. Damodar Valley (West Bengal)
5. Gandhi Sagar (Madhya Pradesh)

Question 18.
In your opinion, what would be the minimum amount of land required to do viable farming which would give a farmer a decent earning. How many farmers in the table Page No. 66 are doing viable farming? (Text Book Page No. 66)
Answer:
The minimum amount of land required to do viable farming may be 2 acres in my opinion. There are 67% of farmers do not have this minimum required land for viable farming.

Question 19.
Why only a small section of farmers have a powerful voice? (Text Book Page No. 66)
Percentage of large and medium farmers is 5% but they hold 32% of total cultivable land. Their average land holding is also high. Hence they have a powerful voice.

SCERT AP Board 9th Class Social Solutions 5th Lesson Biosphere Textbook Questions and Answers.

AP State Syllabus 9th Class Social Studies Solutions 5th Lesson Biosphere

9th Class Social Studies 5th Lesson Biosphere Textbook Questions and Answers

Improve Your Learning

Question 1.
Life itself constitutes a separate sphere called ‘Biosphere’. Explain.
Answer:

• The Earth is a unique planet, in that it has life.
•  It is inhabited by countless forms of life from microscopic bacteria to great banyan trees and animals like lions and blue whales and of course human beings.
• The earth has a combination of land, air and water and a moderate temperature has made life possible on it.
• Various forms of life are not only related to the three spheres around them, but also to one another.
• They influence one another and they are part of a complete “food chain.”
• Hence geographers are of the opinion that “life itself constitutes a separate sphere called ‘Biosphere’.

Question 2.
Why is ecological crisis created in modern times? What are its effects?
Answer:

• These days the increase in population creates great pressure on earth as well as its resources.
• To satisfy the needs of ever growing population systematic mining, cutting of forests, building of forests and fields and roads took place all over the earth.
• Burning of fossil fuels and release of enormous amounts of waste materials by industries contaminate air, water, and soil.
• For providing food for the ever growing population, there is a need for increase in agricultural production.
• Modern agriculture uses a large amount of chemical fertilizers and pesticides.
• The most frightening aspect of pollution due to modern agriculture is the increase in the levels of toxins in our food.
• This increasingly proves to be very harmful not only to humans but also to all types of life on earth.
• Since all living and non-living things on the earth are in one way or the other connected to each other, change affecting one, in due time affects all the others too. All these factors lead to ecological crisis.

Effects of ecological Grisis :

1. If a particular species which feeds upon a particular kind of plant is exterminated, it would result in unchecked growth of that plant and it may intrude the area where other plants grow and disturb their growth.
2. Many industries use chemicals and metals which flow into the rivers and streams. The metals like mercury are consumed by microorganisms in water and in turn beome the food of fishes. When human beings consume these fishes they too absorb some amount of mercury which is detrimental to their health.
3. Farmers use Diclofenac to treat cattle; when the cattle die their flesh retains this chemical: When their flesh is consumed by vultures, diclofenac leads to kidney failure in them and they die.

Question 3.
Natural vegetation depends upon the climate of the place. Write different kinds of forests and climatic conditions of their existence?
Answer:
a) Tropical Deciduous Forests :

1. Tropical deciduous forests are the monsoon forests.
2. These regions experience seasonal changes.
3. Trees shed their leaves in the dry season to conserve water.

b) Tropical Evergreen Forests :

1. These thick forests occur in the regions near the equator and close to the tropics.
2. These regions are hot and receive heavy rainfall throughout the year.
3. As there is no dry season, these trees do not shed their leaves altogether.
4. This is why they are called evergreen forests.

c) Temperate Evergreen Forests :

1. These forests are located in the mid latitudinal costal region.
2. They are commonly found along the eastern margin of the continents.

d) Temperate Deciduous Forests :

1. The temperate deciduous forests are found in higher latitudes.
2. They shed their leaves in the dry season.

e) Mediterranean Vegetation :

1. The west and the south west margins of the continents are covered by these forests.
2. Mediterranean trees adapt themselves to dry summers with the help of their thick barks and wax coated leaves. These help them to reduce transpiration.
3. These regions are marked for hot dry summers and dry summers and mild rainy winters.

f) Coniferous Forests :

1. Coniferous forests are found in the higher latitudes of Northern hemisphere.
2. These forests are found in abundance in the Himalayas.

g) Tropical Grasslands :

1. These forests grow on either side of the equator up to tropics.
2. This vegetation grows in the areas of moderate to low amount of rainfall.

h) Temperate Grasslands :

1. These are found in mid-latitudinal zones and in the interior part of the continents.
2. Usually the grass is very short and nutritious.

i) Thorny Bushes :

1. These are found in the dry desert like regions.
2. This vegetation cover is scarce here because of scanty rain and scorching heat.

j) Tundra :

1. This vegetation is found in the polar region.
2. The growth of natural vegetation is very limited here.
3. Only mosses, lichens and very small shrubs are found here.

Question 4.
How can we protect natural resources?
Answer:
Preservation of the natural environment is essential for maintaining community sustainability.
1. Water:
Communities must work to assure an adequate water supply to meet future needs.

2. Energy :
Energy should be consumed reasonably.

3. Air and climate :
Communities can preserve air quality by limiting or eliminating the discharge of harmful chemicals into the air and by minimizing the sources of air pollution.

4. Biodiversity :
Healthy wildlife should be supported through integrative approaches for, managing, protecting, and enhancing wildlife populations and habitats appropriate to their area and the atmosphere.

5. Land, forests, ecosystems should be provided protective measures. Thus we can protect natural resources.

Question 5.
Read the lesson and fill up the table.

Answer:

Question 6.
Locate the following countries in the world map.
a) New Zealand
b) Brazil
c) Australia
d) North America
e) China
f) India
Answer:

Question 7.
Read the paragraph under the title ‘Depletion of Resources’ on page 57 and comment on it.

Industrialisation, rapid population growth and urbanisation all have meant unprecedented exploitation of natural resources like minerals, forests, soil, water, air etc. besides sources of energy (coal, petroleum etc.) stored in the earth for billions of years. This has resulted in rapid deforestation and decline of reserves of minerals, oil and ground water. Many scientists have argued that the present way of life is not ‘sustainable’for if we use so much natural resources, nothing will be left for our children and grand children.

Answer:
Depletion of resources is the consumption of a resource faster than it can be replenished.

Use of either of these forms of resources beyond their rate of replacement is considered to be resource depletion.

Resource depletion is most commonly used in reference to farming fishings mining, water and fossil fuels.

Question 8.
Visit any nearby industrial establishment and observe the different kinds of smoke, liquid and Solid Wastes come*6uf of the cdrrtp’ourtd. FincTout from the nearby’residents about their impact on plants and animals. Based on the information collected, prepare a report and present in the class.
Answer:
I have visited a cement factory and observed the following :
Cement manufacture causes environmental impacts at all stages of the process. These include air-borne pollution in the form of dust, gases, noise and vibration when operating machinery and during blasting in quarries, and damage to country side from quarrying. Environmental protection also includes the re-integration of quarries.

• CO₂ emissions : Cement manufacturing releases CO₂ in the atmosphere.
• Heavy metal emissions in the air.
• Heavy metals present in the clinker.
• Use of alternative fuels and by-products materials.
• Noise levels are easy to establish.
• Smoke released from the factory causes breathing problems in the local people.
• Waste liquids are sent to the nearest river and pollute the river water.

Question 9.
Collect the details of some endangered animals and birds in your area. Fill the following table. Discuss in the classroom. Take the help of your elders and teachers.

Answer:
Student Activity.

9th Class Social Studies 5th Lesson Biosphere InText Questions and Answers

Question 1.
Can you say how plants are dependent upon air and water and how they affect the two in return? (Text Book Page No. 51)
Answer:

• Plants need water. Plants use water to carry moisture and nutrients from the roots to the leaves and food from the leaves back down to the roots.
• Plants absorb carbon dioxide from air to form carbohydrates during the process of photosynthesis.
• Nitrogen gas molecules that are trapped and carried in the water droplets provide nourishment to plants.
• Plants need oxygen in small amounts in respiration.
• Plants reduce the carbon dioxide levels in atmosphere and reduce the greenhouse effect and in turn the global warming.

How do plants affect water and air in return?
Answer:

• Plants return water to the atmosphere through the process of transpiration.
• Transpiration is the evaporation of water from aerial parts of plants, especially from . leaves but also from stems and flowers.

Question 2.
In what ways are insects like mosquitoes and butterflies dependent upon rocks or soil and upon water ? How do they affect them in return? (Text Book Page No. 51)
Answer:
Many insects depend on soil for part of their life. They make their home in the soils. Some insects live some portion of their lives in water.

Insects get involved lot of biological processes. Among the most significant beneficial impacts of insects on soil are

1. Their role in regulation of pest populations,
2. The pollination of crops and
3. The soil engineering. Insects mostly pollute the water.

Question 3.
Identify the desert regions in the world map.
Answer:

1. The Sahara Desert
2. The Kalahari Desert
3. The Thar Desert
4. The Arabian Desert
5. The Australian Desert
6. The Atacama Desert
7. The Sonaran Desert

Question 4.
Look around in your surroundings and find out the articles made of hard wood and soft wood. (Text Book Page No. 55)
Answer:
A) Articles made of hard wood :

1. Hard woods are often used to make items including furniture, flooring and utensils. Spoons, chopsticks, bowls, plates and cups are the utensils made from hard wood.
2. Musical instruments such as violins, guitars, pianos and hard drums are also made of hard wood.
3. Sofas, chairs, beds, benches, tables and wardrobes are made of hard wood.

B) Articles made of soft wood :
Manufacturing paper, newsprint, decorative articles, carvings, dolls, match boxes and packing boxes, etc. are made from soft wood.

Question 5.
Find out and learn few names of trees of your locality. (Text Book Page No. 55)
Answer:
In our local we can see Neem trees, Mango trees, Banyan trees and the trees are known by their local names: Chinta, Tumma, Seema Tumma, Palm (Tati), Bandaru, Yegisa are the trees which give us wood.

The trees such as Bamboo give us pulp.

Mangoes, Guavas, Blackberry are fruit bearing trees. In addition to them we have coconut trees and trees which give us drumsticks.

Question 6.
Can you discuss how human beings would have impacted the land, water, plants and animals around them when they began agriculture and animal herding? (Text Book Page No. 56)
Answer:

• With the development of agriculture humans began to radically transform the environment in which they lived.
• They cleared the lands around their settlements and controlled the plants that grew and the animals that grazed on them.
• They devised ways of storing rain water and rechanneling river water to irrigate plants.
• They built reservoirs, dug canals, dikes and sluices that permitted water storage.
• They domesticated major food crops, plants such as flax and cotton and began to cultivate them.
• Men also took lead in taming, breeding and raising the large animals associated with both farming and pastoral communities.
• Thus human beings impacted the land water, plants and animals around them when they began agriculture and animal rearing.

Question 7.
What sources of energy would they have used and how would they haveobtained them? (Text Book Page No. 56)
Answer:

1. The growth of sedantary farming greatly accelerated the pace of technological and social change.
2. Still the man used the physical energies of human and animals to use the agricultural and manufacturing tools.
3. He used wheel to make pots, plough to plough his fields and boats to transport his goods and kiln of blacksmith to make his tools.
4. He burnt firewood to cook his food.
5. Thus when they began agriculture man used merely the physical energy of human beings and animals.

Question 8.
Can you say what kinds of changes will building of cities have on the land and water around them? (Text Book Page No. 56)
Answer:

• With the beginning of agriculture and use of better tools give rise to larger, more elaborate and commodious housing and the construction of community ritual centres.
• Sun-dried bricks, interwoven branches usually plastered with mud and stone structures were associated with early agricultural communities.
• Houses in early agricultural settlements included special storage areas. They were centered on clay or stone hearths that were ventilated by a hole in the roof.
• To defend their cities from the rival nomadic settlements, they fortified their cities.
• The people had devised ways of storing rain water and rechanneling river water to irrigate plants.
• The reservoirs and canals, dikes and sluices that permitted water storage were constructed.

Question 9.
In what way do you think this would have affected the land scape and water cycle? (Text Book Page No. 56)
Answer:

• The increase in population create great pressure on earth as well as its resources.
• The entire earth was reshaped to suit the needs of humans.
• The surface of the earth received a great push with the industrial revolution and process of colonization.
• Industrial production needs raw materials on an unprecedunted scale.
• Industrial countries began to search for diverse kinds of raw materials and sources of energy.
• They dug deep wells and tried to find out what lay underneath.
• Systematic mining, cutting of forests, building of factories and fields and roads took place all over the world.
• The cumulative impact of industrial pollution causes greenhouse effect and global warming.
• The greenhouse effect could cause decrease in precipitation and soil moisture content and decrease of snow cover and finally decrease in rainfall.
• The increased surface temperature would cause melting of glaciers and lead to flooding of coastal areas.

 

SCERT AP Board 9th Class Social Solutions 4th Lesson Atmosphere Textbook Questions and Answers.

AP State Syllabus 9th Class Social Studies Solutions 4th Lesson Atmosphere

9th Class Social Studies 4th Lesson Atmosphere Textbook Questions and Answers

Improve Your Learning

Question 1.
Explain the composition of the atmosphere.
Answer:

• The atmosphere is a sea of gases surrounding the Earth.
• There are many gases in the atmosphere.
• Of all the gases in the atmosphere oxygen (21%) and nitrogen (78%) dominate.
• Other gases are in very small percentages, these include argon, neon, carbon dioxide (0.03%), methane, ammonia, ozone, etc.
• Water vapour accounts for about 0.4% by volume over the whole atmosphere.
• Apart from these gases the atmosphere also has the fine dust particles called particulates.

Question 2.
Discuss the structure of the atmosphere along with a diagram.
Answer:
On the basis of the chemical composition the atmosphere is divided into two broad layers. They are -1) Homosphere II) Heterosphere
I) Homosphere : This layer is characterized by uniformity in composition of gases like
Nitrogen, Oxygen, Orgon and Carbondioxide. It consists of the three thermal layers such as Troposphere, Stratosphere and Mesosphere. It extends up to the height of 90 kms.

A) Troposphere :
i) It is the lower most of layers of the atmosphere.
ii) It extends to a height of 8 kms near the poles and about 18 kms at the equator.
iii) It contains 75% of the total gaseous mass of the atmosphere.
iv) The entire weather phenomenon happens in this layer.
v) The life is present in this layer.

B) Stratosphere :
i) This layer extends up to a height of 50 kms.
ii) This layer is free from clouds and associated weather phenomenon.
iii) These conditions are most ideal for flying jet aircrafts.
iv) This layer contains Ozone layer.

C) Mesosphere :
i) It extends up to a height of 80 kms.
ii) Meteorites burn up as they enter this layer from the space.
iii) The temperature starts decreasing with the increase in altitude.

II) Heterosphere : Because of its heterogenous composition this layer is called heterosphere. This layer is above 90 kms of the atmosphere. It has two thermal layers called Thermosphere and Exosphere.
A) Thermosphere:
i) It extends up to 400 kms.
ii) Here the temperature rises rapidly with increase in height.
iii) It contains electrically charged particles known as ions. Hence this layer is called Ionosphere.
iv) Radio waves are reflected back to the earth through this layer.
v) It is also known as ‘Ionosphere’.

B) Exosphere :
i) The upper most layer of the atmosphere.
ii) Very little is known about this layer.

Question 3.
Differentiate weather and climate.
(OR)
Write the differences between weather and climate?
Answer:

• The difference between weather and climate is a measure of time.
• Weather is what conditions of the atmosphere are over a short period of time and climate is how the atmosphere “behaves” over relatively long period of time.
• Weather is basically the way the atmosphere is behaving, mainly with respect to its effects upon life and human activities.
• Whereas climate is the description of the long-term pattern of weather in a particular area.
• In most places weather can change from minute to minute, hour to hour, day-to-day and season-to-season. Whereas the climate is the average of weather overtime and space.
• In short, climate is what we expect whether a hot summer or a cool winter and weather is what you get or experience at present.

Question 4.
Compare and contrast convectional and orographic rainfall.
Answer:
Comparison between convectional and orographic rainfall:
1) Both types of rainfall are caused by vertical ascent of heated air.
Contrast between convectional and orographic rainfall :

1. While orographic rainfall is caused when the mountain forces the air to rise over mountain or the elevation in its path; the convectional rainfall occurs when moisture over the heated ground becomes warmer than the surrounding air.
2. While convectional rainfall is common on summer days in interior part of the continents the orographic rainfall occurs in the windward sides of mountains.
3. While the orographic rain occurs in the mountainous regions, the convectional rain takes place in the equatorial regions.

Question 5.
Describe the distribution of world rainfall.
Answer:

• Between the latitudes 10° and 30° N and S of the equator, due to the trade winds, rainfall is heavier on the eastern coasts, and decreases towards the West.
• Between the latitudes 40° and 60° N and S of the equator due to the westerlies, the rainfall is heavy on the west coast, and goes decreases towards the East.
• Low pressure areas, especially around the equator receiver high rainfall than high pressure areas.
• The rainfall is more over the oceans than on the continent.

Question 6.
How do climatic changes influence the human life?
Answer:
Due to climatic changes the following changes are taking place.

1. The climatic changes led to the emergence of large scale environmental hazards such as global warming, increase of green house gases etc.
2. Development of planet’s flora and fauna is mainly due to climatic changes.
3. Globally the average sea level has risen by 17 cm in the 20th century.
4. Climatic changes are affecting food habits and culture of the people of any area.
5. Due to global warming both the Greenland and Antarctic ice sheets have lost significant amounts of ice.
6. Thus the climatic changes are influencing human life significantly.

Question 7.
Explain relative humidity.
Answer:

• The amount of water vapour present in the atmosphere is called humidity.
• Relative humidity is the ratio between the maximum water vapour that the air can hold at a given temperature and pressure and the actual amount of water vapour it holds at any given time.
• For example, at 20°C temperature air can contain 80 gms of water vapour per cubic meter. If the actual water vapour present is 40 gms, the relative humidity is 50%.
• If the atmosphere has 100% relative humidity, it is known as saturation level.
• Relative humidity decreases with increase of temperature and decrease of water vapour,
• In high humidity, our sweat doesn’t cool us because it cannot evaporate.
• In low humidity we feel more thirsty.

Question 8.
Why does the amount of water vapour decrease rapidly with altitude?
Answer:
The water vapour is attracted towards the surface or close to the surface due to the gravitational pull of the earth. Hence the amount of water vapour decreases with altitude.

Question 9.
What is Coriolis effect ? And explain its effects.
(OR)

“Vasco da Gama found the sea route to India using winds to power his ships. Europeans established colonial states in various parts of the world through the wind power”.

What is Coriolis effect and how does it influence the wind system?
Answer:
1. Because of the impact of Earth’s rotation on its own axis, the winds move slightly to the right in the northern hemisphere, and to the left in the southern hemisphere. This effect is called Coriolis effect.
2.

3. At the equator the Coriolis effect is ‘O’ and at the poles it is maximum.

The most important effects of Coriolis force are :
a) The deflection of winds and currents in the ocean.
b) It has significant effect on planes and missiles also.
c) In the northern hemisphere these winds move to the right and in the southern hemisphere to the left. This usually creates the westerly winds moving from the subtropical areas to the poles.
d) The Coriolis effect also affects the movement of ocean currents.

Question 10.
Identify the given local winds in the world map.
a) Chinook
b) Loo
c) Simoon
d) Yoma
e) Norwester
f) Mistral
g) Puna
h) Pampero
Answer:

Question 11.
Read the para under the title “Effects of Planetary Winds” on page 43 and comment on it.
Effects of Planetary Winds: You would have noted that the pressure and wind systems are actually a result of the impact of Lithosphere and Hydrosphere on Atmosphere. These winds play a crucial role in transporting heat and moisture across the world. That is why no part of the world gets too cold or too hot for life to survive. Had there been no atmosphere (as on the Moon) it would have got intolerably hot in day time or in the tropics and intolerably cold at night or in the Polar regions. However, these winds do not distribute heat or moisture uniformly – which is why we have some parts of the earth quite hot, some parts cooler and some parts with high rainfall and some which are deserts.
Answer:
Planetary winds are winds that are created in the different Global circulation cells.

1. Polar Easterlies – blow from pole to 60°
2. Prevailing Westerlies – blow from 60° to 30°
3. Trade Winds – blow from 30° to 0°

These winds transport heat and moisture across the world. But the winds do not distribute heat or moisture uniformly.

Question 12.
Collect weather information covered by media such as newspaper, TV, Radio, etc. to understand weather phenomenon.
Answer:
Weather information of major cities of India on 8, April 2020.

Delhi	47°C	Afternoon, Thu 17:04
Jabalpur	50°C	Afternoon, Thu 17:04
Chennai	41°C	Afternoon, Thu 17:04
Banglore	45°C	Afternoon, Thu 17:04
Ahmadabad	sere	Afternoon, Thu 17:04
Allahabad	39°C	Afternoon, Thu 17:04
Pune	34°C	Afternoon, Thu 17:04
Poona	25°C	Afternoon, Thu 17:04
Haora	33°C	Afternoon, Thu 17:04
Surat	32°C	Afternoon, Thu 17:04
Madras	41°C	Afternoon, Thu 17:04
Calcutta	34°C	Afternoon, Thu 17:04
Solapur	40°C	Afternoon, Thu 17:04
Muzaffarpur	50°C	Afternoon, Thu 17:04
Bulandshahr	37°C	Afternoon, Thu 17:04
Ghaziabad	46°C	Afternoon, Thu 17:04
Jaipur	37°C	Afternoon, Thu 17:04
Kanpur	48°C	Afternoon, Thu 17:04
Lucknow	38°C	Afternoon, Thu 17:04
M 0 Ranchi	49°C	Afternoon, Thu 17:04
Nagpur	53°C	Afternoon, Thu 17:04
Visakhapatnam	32°C	Afternoon, Thu 17:04
Guwahati	26°C	Afternoon, Thu 17:04
Chittoor	46°C	Afternoon, Thu 17:04
Indore	37°C	Afternoon, Thu 17:04
Coimbatore Peelamedu	35°C	Afternoon, Thu 17:04
Kalya n	35°C	Afternoon, Thu 17:04
Patna	39°C	Afternoon, Thu 17:04
Kozhikode	30°C	Afternoon, Thu 17:04
Gwalior	37°C	Afternoon, Thu 17:04
Jamnagar	42°C	Afternoon, Thu 17:04
Vadodara	38°C	Afternoon, Thu 17:04
Mahesana	36°C	Afternoon, Thu 17:04
Akola	41°C	Afternoon, Thy 17:04
Bhopal	39°C	Afternoon, Thu 17:04
Ludhiana	47°C	Afternoon, Thu 17:04
Aurangabad	51°C	Afternoon, Thu 17:04
Agra	37°C	Afternoon, Thu 17:04
Cochin	39°C	Afternoon, Thu 17:04
Benares	39°C	Afternoon, Thu 17:04

Question 13.
Collect the newspapers from July to December and note down the news related to extreme rainfall in different parts of country.
Answer:
Average annual rainfall of the states of India

State	Meteorological Divisions	Average annual rainfall (mm)
Andaman and Nicobar Islands	Andaman and Nicobar Islands	2,967
Arunachal Pradesh	Arunachal Pradesh	2,782
Assom	Assom and Meghalaya	2,818
Meghalaya	Assom and Meghalaya	2,818
Nagaland	Nagaland, Manipur, Mizoram and Tripura	1,881
Manipur	Nagaland, Manipur, Mizoram and Tripura	1,881
Mizoram	Nagaland, Manipur, Mizoram and Tripura	1,881
Tripura	Nagaland, Manipur, Mizoram and Tripura	1,881
West Bengal	Sub-Himalayan West Bengal and Sikkim Gangetic West Bengal	2,739 1,439
Sikkim	Sub-Himalayan West Bengal and Sikkim	2,739
Odisha	Odisha	1,489
Bihar	Bihar Plateau	1,326
	Bihar Plains	1,186
Uttar Pradesh	Uttar Pradesh	1,025
	Plain of West Uttar Pradesh	896
	Hills of West Uttar Pradesh	1,667
Haryana	Haryana, Chandigarh and Delhi	617
Delhi	Haryana, Chandigarh and Delhi	617
Chandigarh	Haryana, Chandigarh and Delhi	617
Punjab	Punjab	649
Himachal Pradesh	Himachal Pradesh	1,251
Jammu and Kashmir	Jammu and Kashmir	1,011
Rajasthan	West Rajasthan	313
	East Rajasthan	675
Madhya Pradesh	Madhya Pradesh	1,017
	East Madhya Pradesh	1,338
Gujarat	Gujarat region	1,107
	Saurashtra and Kachchh	578
Goa	Konkan and Goa	3,005
Maharashtra	Madhya Maharashtra	901
	Marathwada	882
	Vidarbha	1,034
Andhra Pradesh	Coastal Andhra Pradesh	1,094
	Rayalaseema	680
Tamilnadu	Tamilnadu and Pondicherry	998
Pondicherry	Tamilnadu and Pondicherry	998
Karnataka	Coastal Karnataka	3,456
	North Interior Karnataka	731
	South Interior Karnataka	1,126
Kerala	Kerala	3,055
Telangana	Telangana	961

9th Class Social Studies 4th Lesson Atmosphere InText Questions and Answers

Question 1.
List out some of the ways in which particulates in the atmosphere are beneficial and harmful to us. (Text Book Page No. 37)
Answer:
1. The fine dust particles present in the atmosphere are called particulates.

2. Particulates may come from natural processes such as sand storms over deserts and natural forest fires and from human activity such as burning forests, burning petroleum and industrial emissions.

3) Benefits of particulates :
a) The particulates can change atmospheric conditions that may be beneficial to life on Earth.
b) The particulates in the atmosphere cause the bright colour of the sunrise or sunset.
c) The particulates help rainfall and hailstones to fall.

4) Harmful effects of particulates :
a) They cause problems by altering temperature and rainfall patterns.
b) They can make it difficult for people to breathe.
c) They can make it difficult for the plants to breathe and photosynthesise.

Question 2.
In which layer is the life present? (Text Book Page No. 39)
Answer:
In troposphere the life is present. The suitable conditions that make life possible in the troposphere are :

1. The troposphere is the lower most layer of the atmosphere.
2. It contains about 75% of the total gaseous mass of the atmosphere and practically all the moisture and dust particles.
3. The entire weather phenomenon happens in this sphere.
4. Condensation, evaporation, precipitation, rainfall, cyclones etc., occur in this layer.

Question 3.
About which layer do we have very less knowledge? (Text Book Page No. 39)
Answer:

• Exosphere is the upper most layer of the atmosphere.
• This is the highest layer.
• Very less is known about it.

Question 4.
Which layer of the atmosphere is ideal for flying jet aircrafts? Why? (Text Book Page No. 39)
Answer:

• Stratosphere is ideal for flying jet aircrafts.
• Because this layer is almost free from clouds and associated weather phenomenon.
• These conditions are most ideal for flying jet aircrafts in this layer.

Question 5.
Our skin dries up more during winters. Why?
Answer:

• Water vapour (i.e., the humidity) is a very important component in the atmosphere.
• The relative humidity plays a large role in determining our comfort level.
• If the relative humidity is 100 percent, we feel much hotter than the actual temperature indicates because our skin, sweat does not evaporate at all.
• If the humidity is low, our skin and mucous membranes are dry.
• As a result of low humidity, we’ll have chapped lips, dry and itchy skin, and a dry sore throat when we wake up in the morning.
• Low humidity also dries the plants and furniture.

Question 6.
Observe the following figure and describe from which pressure belt to which pressure belt are the Westerlies, trade winds and polar Easterlies are blowing.

Answer:

• The Westerlies blow from subtropical high pressure belts to sub polar low pressure belts in both the hemispheres.
• The trade winds blow from sub tropical high pressure belt to equatorial IQW pressure belt.
• Polar Easterlies blow from polar high pressure belt to polar low pressure belt.

Question 7.
What will happen if water vapour is not present in air?
Answer:
1. The condensation of water vapour to the liquid or ice phase is responsible for clouds, rain, snow and other precipitations.

If water vapour is not present in the atmosphere, clouds, rains, snow will not occur. If there is no rain, life will not be possible on earth.

2. Water vapour is one of the green house gases. Green house gases play a major role in determining the balance of between the amount of radiation entering the Earth’s surface and the amount of radiation leaving the Earth’s surface.

The green house effect keeps the Earth’s surface about 33°C warmer thair-it would otherwise be.

Question 8.
Why is atmosphere important for us?
Answer:

• We breathe in oxygen which is one of the components of atmosphere.
• We breathe out carbon dioxide, which in turn is taken in by plants in their respiration.
• The atmosphere prevents harmful rays of the sun from reaching us.
• The green plants take in carbon dioxide, use sunlight and water to photosynthesise and we get delicious fruits, vegetables, and grains from them.
• These give us proteins, carbohydrates, sugars, fats, minerals and other nutrients that we need.
• The atmospheric winds transport water from the oceans deep into the continents in the form of rain.
• Atmospheric winds erode rocks and are responsible for the formation of many kinds of soils with whose fertility we grow many kinds of crops.
• Atmosphere helps in cooling monsoon rains.
• Atmosphere helps in diffusion of perfumes and helps in the travelling of sound waves.
• Thus we can say atmosphere is important for us.

Question 9.
Can you imagine why life is not possible on the Moon? (Text Book Page No. 37)
Answer:

• Life is not possible on the Moon because the Moon has no atmosphere.
• On Moon we don’t have atmospheric pressure without which we cannot live.
• Because of lack of atmosphere we don’t have any protection from ultra violet raditation.
• Because of the lack of magnetosphere, we will be frequently bombarded by the charged particles.
• There is no water on the Moon which is the first and foremost requirement for the life.
• For all the above reasons life is not possible on the Moon.

 

SCERT AP Board 9th Class Social Solutions 3rd Lesson Hydrosphere Textbook Questions and Answers.

AP State Syllabus 9th Class Social Studies Solutions 3rd Lesson Hydrosphere

9th Class Social Studies 3rd Lesson Hydrosphere Textbook Questions and Answers

Improve Your Learning

Question 1.
Find the odd one out and give an explanation for your choice.
i) a) evaporation
b) condensation
c) salination
d) precipitation
Answer:
Odd one – (c)
Except salination, remaining all belong to the water cycle.

ii) a) tectonics
b) centrifugal force
c) solar energy
d) precipitation
Answer:
a) Tectonics is odd one : Remaining all are the factors that cause ocean currents.

Question 2.
Correct the false statements.
a) Oceans trenches can be located near the continents.
b) Relief features of the oceans are like plains.
c) Most salt in the seas is washed into it from the land over centuries.
d) Temperature of ocean water remains the same across the globe.
Answer:
a) Ocean trenches are the deepest parts of the ocean floor.
b) Relief features of the oceans are Trenches, Deep sea plains and Ridges.
c) True.
d) Temperature of ocean water varies from place to place across the globe.

Question 3.
Describe any one impact of ocean currents for the region you live.
Answer:
The Indian Monsoon current refers to the seasonally varying ocean current regime found in the tropical regions of the northern Indian ocean. The seasonally reversing open ocean currents that pass through south of India are referred to as the winter monsoon current and the summer monsoon current, alternately the north-east monsoon current and the southwest monsoon current.

India receives rainfall due to these currents.

Question 4.
Do you think that the description of blue planet is accurate? Describe any one way in which your activity impacts its oceans.
Answer:
Yes, I do think that the description of blue planet is accurate.

Humans are a part of the natural environment. But our activities lead to degradation of environment.

Oceans are suffering from our activities too, our land practices cause agricultural runoff, sewage, and litter to end up in the oceans daily. Today oceans have also fallen victim to our exploitation. Many large fishes like whales have been disappearing. Damage to oceans is damage to our livelihoods, well-being and nourishment.

Question 5.
Why differences are there in the salinity of oceans?
Answer:

• Salinity of ocean water depends upon many causes, but the main cause is continuous movement of ocean. Water from one place to other due to rotation of earth and winds which takes water here and there causing change in salinity of ocean water (ocean currents and thermohaline currents)
• Melting of ice causes an influx of fresh water, which dilutes ocean water.
• inflow of river water causes an influx of fresh water, which dilutes ocean water.
• Evaporation is only fresh water, which removes fresh water flow an area, causing salt to become more concentrated.
• Rain and snowfall opposite of evaporation, we are adding fresh water and diluting it.
• Wave and wind – various local mixing causes smaller – scale variation in surface salinity.

Question 6.
How is human life dependent upon oceans?
(OR)
How is human life depends on Oceans?
(OR)
How are oceans influencing human life?
Answer:

• Oceans stabilize climates over land.
• They are the storehouses of many chemicals, each of which are useful to humans.
• They disperse many plant & animal species from one continent to another, making biota available in various places. Many of these plants & animals are used as food, neutraceutically as medicines.
• Some people constantly live on boat, due to paucity of land in such areas.
• They are a source of various types of poly-metallic nodules.
• They are used for landing of certain debris of satellites & safely pad most of the meteors that come from outer space, as oceans cover more than 75% of earth’s surface.

Question 7.
Observe the map 1 on page 35 and write down the names of a few warm and cold currents.
Answer:
Some warm and cold currents :

1. Equatorial current (warm)
2. Gulf stream (warm)
3. Labrador current (cool)
4. Greenland current (cool)
5. North Pacific current (warm)
6. West wind drift (cool)
7. East wind drift (cool)
8. Bengula current (warm/cool)

Question 8.
Read the para ‘Ocean as a Resource’ on page 33 and comment on it.
Ocean as a ResourceMost life on earth is under the water. Human beings still have not finished identifying all the different forms of life in the oceans. Human beings have depended on oceans for their food and livelihood from the ancient times. Oceans provided abundant food resources like fish and salt. We also use the sand, gravel, etc. for our industries or housing. Humans extract minerals like chlorine, fluroine, iodine from it. Ocean waves are used for generating power. Ocean floor is mined for oils. Oceans also provide us with gems and pearls. For centuries, we have created our civilisations on its shores and traded across with each other travelling on them.
Answer:
The ocean is one of earth’s most valuable natural resources. It provides food in the form of fish and shell fish. It is used for transportation – both travelling and shipping. It provides a treasured source of recreation for humans. It is mined for minerals and drilled for crude oil.

Question 9.
Prepare a flow chart which shows different land forms.
Answer:

Question 10.
Prepare a list of currents which are found in the Pacific, Atlantic and Indian oceans. Identify the cold and warm currents in different oceans.
Answer:

9th Class Social Studies 3rd Lesson Hydrosphere InText Questions and Answers

Question 1.
Give the reasons for the Sow salinity of Baltic sea. (Text Book Page No. 32)
Answer:

1. Baltic sea is a brackish mediterranean sea located between Central and Northern Europe.
2. The Baltic sea’s salinity is much lower than that of ocean water.
3. Baltic is a small sea on a global scale.
4. The causes for the low salinity of the Baltic sea are
   a) The abundant fresh water run off from the surrounding land.
   b) The shallowness of the sea.
   c) The flow of fresh water into the sea from approximately two hundred rivers and the introduction of salt from the south builds up a gradient of salinity in the Baltic sea.
   d) The Baltic sea is only connected to the world’s oceans by the narrow and shallow waters of the Sound and Belt-sea.
   e) This limits the exchange of water with the North sea and means that the same water remains in the Baltic for a lot of years.

For all the above reasons the salinity of the Baltic sea is less than that of the salinity of the oceans.

SCERT AP Board 9th Class Social Solutions 2nd Lesson The Natural Realms of the Earth Textbook Questions and Answers.

AP State Syllabus 9th Class Social Studies Solutions 2nd Lesson The Natural Realms of the Earth

9th Class Social Studies 2nd Lesson The Natural Realms of the Earth Textbook Questions and Answers

Improve Your Learning

Question 1.
Fill in the blanks.
a) Hydrosphere is related to …………………….. .
b) Lithosphere is related to …………………….. .
c) Atmosphere is related to …………………….. .
d) Biosphere is related to …………………….. .
Answer:
a) water mass
b) land mass
c) air mass
d) life

Question 2.
Find the odd one out in the context of lithosphere and give reasons for your choice.
Byson gorge; Grand Canyon; Ozone; Thar desert.
Answer:
Out of these four ozone is the odd one.
Reasons:

1. Byson gorge and Grand canyon are hilly areas.
2. Rivers flow through them.
3. Plants and trees are present there.
4. Thar desert is a vast sand desert, with no water. It has thorny bushes and some kinds of desert plantations.
5. Above three are landforms.
6. But Ozone is an inorganic molecule with the chemical formula 03. It is a pale blue gas with a distinctively pungent smell. Ozone’s 03 formula was determined in 1865.

Question 3.
How is the Lithosphere formed?
Answer:

• The solid crust or the hard top part of the earth is called lithosphere.
• The crust is made up of rocks and minerals and covered with a thick layer of soil.
• It is uneven and has high mountains, plateaus, plains, and very deep basins.
• Many of these features are shaped by internal and external processes.
• The slow movements inside the earth lead to the formation of the crust.
• The sudden movements can damage and lead to changes in landforms.
• The processes originating from the depths of the earth like earthquakes and the volcanic eruptions play important role in shaping the surface of the earth.
• The external sources like wind, water, glaciers, and waves also play prominent role in shaping the lithosphere.

Question 4.
How are the continental plates formed and how are they eventually destroyed?
Answer:

• In the beginning, probably all continents were held together.
• Later the earth’s lithosphere is broken up into several pieces, just like the pieces of a large jigsaw puzzle and thus continental plates formed.
• These pieces, on which all the continents and oceans are actually situated, are called “Plates”.
• They float on soft layer of the mantle.
• There are about seven major plates and several minor plates on the earth.
• As the plates move, they push, pull, slide, rise, sink, bend and break.
• Sometimes one plate meets another, the incoming plate dips under the stable plate.
• In fact the incoming plate actually goes into the mantle of the earth and becomes molten due to the heat of the mantle.
• That is how some plates are eventually destroyed.

Question 5.
List out the landforms formed due to the river work. (AS1)
Answer:
Many landforms are formed due to the work of the river. They are
1. V – shaped valley:
The flow of a river is very swift as it descends the steep slopes and it exerts a great force in cutting the mountain vertically. As a result a deep valley develops, narrow at the bottom and wide at the top. This is called V – shaped valley.

2. Gorge:
Where the rocks are very hard, the river cuts a narrow valley with steep sides called Gorges.

3. Canyon:
A deep valley with steep like slopes and is wider at its top than at the bottom is called a Canyon.

4. A plunge pool:
The water falls with great force and dig out the rock beneath to form a plunge pool.

5. Plain:
When the river is in floods it cuts the soil and when it is not in flood it deposits silt and thus forms vast flood plains.

6. Meanders:
As a result of the deposition by floods the river bed becomes too high, the river constantly changes its course and cuts new path and forms gentle snake like meanders.

7. Ox-bow lakes:
Due to the deposition along the sides of the meanders, the ends of the meander loop comes closer and closer. In the course of time the meander loop cuts off from the river and forms a cut off lake which is called ox-bow lake.

8. Delta:
When a river reaches the sea, the fine material is deposited at its mouth forming a delta (∆).

9. Ozone:
Ozone is an inorganic molecule with the chemical formula 03. It is a pale blue gas with a distinctively pungent smell. Ozone’s 03 formula was determined in 1865.

Question 6.
Create a table as given below and fill information. And write a small paragraph to explain the similarities and differences you can think of in the context of earth’s external changes, (if there is no information available in the text, leave those columns blank)

	Wind	Water	Glacier
Landform
Process

Answer:
Wind:
Wind takes many forms and carries away the surface of the land in the higher places.

Water :

1. Water reacts with the chemicals of the rocks and further weakens the rock.
   Water acts as moving agent of the earth.

Glacier :

1. The ice on these glaciers melt throughout the year and flows to low areas as rivers and streams.
2. They also erode, transport and deposit rock materials.

Two forces, weathering and erosion, are constantly at work building up and moving rocks making up the earth’s crust.

Weathering causes rocks to fragment, crack, crumble, or break down physically and chemically.

Erosion loosens and carries away the rock debris formed by weathering. Over time these two forces, working together, change the shape of the land.

Question 7.
Why are Glaciers not found in your surroundings?
Answer:
Glaciers are most commonly found above snow line i.e., regions of high snow fall in winter and cool temperatures in summer. These conditions allow more snow to accumulate on the glacier in the winter that will melt in the summer. This is why most glaciers are found either in mountainous areas or the polar regions.

We are in the state of Andhra Pradesh. It is a semi-arid area and has a predominantly hot and dry climate. Summers start in March, and peak in May with average high temperatures in the 42°C range. A dry, mild winter starts in late November and lasts until early February with little humidity and average temperatures in the 22°C – 23°C range. In such hot and dry conditions glaciers are not formed. So we cannot find glaciers in our surroundings.

Question 8.
How are Beaches formed and name some Beaches?
Answer:
Formation of Beaches:

1. Sea water contains sediments like sand, pebbles, etc.
2. Beaches form as waves deposit these sediment on the shore.
3. The wind pushes these sediments on the shore and inland.
4. This creates an area of sand particles finally form a beach.

Names of some beaches :

1. Diu Beach
2. Manori Beach, Mumbai
3. Versova Beach, Mumbai
4. Mivamar Beach, Panaji
5. Karwar Beach, Karnataka
6. Fort Kochi, Cochin
7. Kovalam Beach, Trivandrum
8. Marina Beach, Chennai
9. R.K. Beach, Visakhapatnam
10. Chandipur Beach, Odisha.

Question 9.
How is the human lifestyle responsible for extension of deserts?
Answer:

• Desertification can be considered as a set of biological, chemical, and physical processes which converge to create desert-like conditions.
• Desertification is a social problem involving people at all stages as a cause and as victims.
• The anthropogenic (human) causes of desertification are over cultivation, over grazing, deforestation and poor irrigation practices.
• These factors are fuelled by local forces such as poverty and population pressure.
• Increase in temperature leads to drying out of water and it further causes to expansion of deserts.
• Mismanagement of dry land ecosystems by humans can cause desertification.
• Poor land use and overgrazing are significant factors for the expansion of deserts.
• Thus activities of human beings lead to the extension of deserts.

Question 10.
Find out the order of the landforms for the following.

Landform	Order of Landform
The Himalayan Mountains	II order Landform
The Pacific Ocean
Asia Continent
Byson Gorge
Jog waterfall
Rocky mountains
The Indian Ocean
The great rift valley

Answer:

Landform	Order of Landform
The Himalayan Mountains	II order Landform
The Pacific Ocean	1 order Landform
Asia Continent	1 order Landform
Byson Gorge	III order Landform
Jog waterfall	III order Landform
Rocky mountains	II order Landform
The Indian Ocean	1 order Landform
The great rift valley	III order Landform

Question 11.
Draw the map of world plates by observing map 2.
Answer:

Question 12.
Read the para under the title ‘Erosion’ on page 20 and comment on it.

Erosion : Flowing water and wind have great power and can slowly wear away or cut away the rocks and soil cover in higher places. Water acts in many ways, as rain, river, flowing ground water, sea waves, glaciers etc. Wind too takes many forms like storms, gusts, steady winds, etc. The active wearing away of the earth’s surface by these moving agents is called erosion.

Answer:
Erosion is the process by which soil and rock are removed from the earth’s surface by exogenic processes such as wind or water flow, and then transported andsdeposited on their locations while erosion is a natural process. Human activities have increased by 10 – 40 times the rate of which erosion is occuring globally.

Question 13.
Collect newspaper or magazine articles and news on earthquakes and volcanoes.
Prepare an illustrated file on these – how do they happen and how they affect human life.
Answer:
Student’s activity.
Ex: Earthquakes:
The earth’s surface is formed of massive slabs of rock called plates. These are called tectonic plates, are always moving. Sometimes they just slide past one another. At another time they actually collide with one another. Plate movements cause the build up of tremendous quantities of energy in the rock. When the energy is released, it produces vibrations that travel through the rock, leading to earthquakes. During earthquakes, faults, or giant cracks, are produced by the pressure of moving rocks.

Volcanoes:
Deep within the earth it is so hot that some rocks slowly melt and become a thick flowing substance called magma. Because it is lighter than the solid rock around it, magma rises and collects in magma chambers. Eventually some of the magma pushes through vents and fissures in the earth’s surface. Then a volcanic eruption occurs.

Their effect on human life :

1. Major earthquakes and volcano eruption can affect human life.
2. Roads can be damaged and delivery of food can be disrupted.
3. Clean, drinking water may not be available.
4. Sewer system may leave, causing diseases.
5. Gas line could leak, causing health issue.
6. All the surroundings can get covered with ash.
7. Communication system fails.
8. They destroy property and threaten human lives.

9th Class Social Studies 2nd Lesson The Natural Realms of the Earth InText Questions and Answers

Question 1.
Why do you think the rock is harder inside than outside? (Text Book Page No. 20)
Answer:

• The gradual disintegration of rocks is caused by atmosphere forces.
• The rocks when exposed to heat expand and contract when cooled down.
• As surface rock contracts and expands and contracts again, it gradually becomes brittle and begins to break down.
• Water reacts with the chemicals in the rock and further weakens it.
• These processes by which the rocks are weakened and broken are called ‘weathering’.
• It is easier to chip small pieces of rock from the outer layer rather than from the core of the rock.
• Thus we can say the rocks are harder inside than outside.

Question 2.
Expalin how are the waterfalls are useful. (Text Book Page No. 22)
Answer:

• The most noted advantage of waterfalls is their ability to produce hydroelectric power.
• As it descends the steep slopes the waterfall exerts a great force and cuts mountains vertically and forms V-shaped valleys, gorges and canyons.
• These attract many tourists throughout the world and earn a lot of foreign exchange.
• Waterfalls put oxygen into the water which first helps the fish breathe well.

Question 3.
Can you discuss in the class how the following human actions impact the lithosphere?
i) Mining
ii) Building cities with bricks and cement
iii) Agriculture
iv) Dams (Text Book Page No. 25)
(OR)
‘Human actions like mining, building cities with bricks and cement, agriculture and dams are impacting the lithosphere’ – Comment on it. Mra
Answer:
i) Impact of mining on lithosphere :

• Mining disturbs and removes the rocks, ores and minerals in the geosphere.
• It leaves huge gaping holes in the earth.
• The mine tailings are pulled up in large mounds on the surface of the geosphere.
• Subsidence is an effect that occurs above a deep mine.
• The deep mines cause redistribution of the existing tectonic stress field disturbed by the excavation process.
• High stresses exist inside tectonic plates and they are sensitive to any perturbations.
• In case of mining the mass removal causes fault zones and eventually earthquakes.

ii) Impact of building cities with brick and cement on lithosphere:
Constructing buildings with cement and bricks has a lot of negative effects.

• Concrete used to create hard surfaces causes to surface turn off and it can cause heavy soil erosion.
• Constructing the buildings with cement, bricks and concrete have different thermal and hydrological properties. These cause the surface absorbs and stores heat and water.

iii) Impact of agriculture on lithosphere:
Man has been trying to manipulate more and more of nature and exploit this natural resource by the unscientific practice of agriculture.

• Agriculture causes the depletion of underground acquifiers through overdrafting.
• Under irrigation gives poor soil salinity control which leads to increase soil salinity with consequent build up of toxic salts on soil surface.
• Wide use of agricultural chemicals causes soil pollution.

iv) Impact of dams on lithosphere :

• As a result of dam construction and holding of sediments in reservoirs sediment feeding of down stream channel or shore beaches is prevented.
• Corrosions may occur.
• Rare archaeological and historical places with their exceptional beauties disppear after lying under the reservoir.
• Earthquakes and volcanic activity can be induced by the weight of the reservoir on nearby faulty lines.
• Soil erosion of silt deposited at the edges of reservoirs can seriously damage surrounding vegetation and farmland by sand blow.

Question 4.
Write an imaginary description of the damages that occur due to volcanic eruption in an area. (Text Book Page No. 19)
Answer:

• Volcanic eruption can cause earthquakes, fast floods, mudslides and rock falls.
• Lava can travel very far and burn, bury or damage anything in its path including people, houses and trees.
• The large amount of dust and ash can cause roofs to fall, makes it hard to breathe and is normally very smelly.
• The ground around volcano is not secure and can cause big earthquakes.
• Big volcanic eruptions can change the weather around the world.
• Ash clouds float very high in the air and can cause snow and frost in the summer in a lot of countries.

Question 5.
Compare the Loess Plains with a Delta. What similarities and differences do you see between them? (Text Book Page No. 25)
Answer:
Similarities between Loess Plains and Deltas :

1. Both are the deposits of erosional fine materials on plains.
2. Both loess plains and deltas are fertile lands.

Differences between Loess Plains and Deltas:

1. While loess plains are formed with fine dust blown beyond the deserts, the deltas are formed with fine alluvial material transported by the rivers.
2. While loess plains are formed in the neighbouring lands of the deserts, the deltas are formed at the mouths of the rivers.
3. While loess are fine loam, rich in lime, very coherent and extremely porous, the deltas consist of clayey alluvial soils with a mixture of organic material.
4. While deltas are formed by the action of rivers, the loess plains are formed by the action of winds.

Question 6.
Geologists have found fossils of sea animals on the Himalayas. Some of these are actually worshipped in many homes as ’Salagramas’. How do you think are these^ossil^here on the Himalayas? (Text Book Page No. 17)
Answer:

• The Himalayas are formed by the collision of the Indian and Eurasian land masses which were originally separate.
• This collision uplifts mountains.
• From around 200 million years ago the area between the two separate land masses was covered by the Tethys sea, which was filling with sediments and had sea creatures which left fossils in the sedimentary rocks formed there.
• So the fossils found in the Himalayas are those formed in the ancient sea bed of the Tethys sea, now exposed and pushed up to form mountains.
• Salagramas are usually black coloured spherical fossils found in the sacred river Gandaki.
• The name salagrama refers to the name of the village on the bank of the Gandaki, where the holy stones are picked up.
• Hindus consider these salagramas as an iconic representation of Vishnu and worship these salagramas.

Question 7.
Collect information about the waterfalls in Andhra Pradesh. (Text Book Page No. 22)
Answer:
Waterfalls of Telangana :

1. Ethipothala falls, near Nagarjuna Sagar Dam.
2. Katiki waterfalls – Visakhapatnam district
3. Kailasakona falls – Chittoor district
4. Mallelatheertham – Nallamala forest, Kurnool district
5. Penchalakona falls – Nellore district
6. Rampachodavaram – East Godavari district
7. Talakona falls – Chittoor district
8. Ubbalamadugu or Tada falls – Chittoor district

Question 8.
Collect some of the pictures of waterfalls. (Text Book Page No. 22)
Answer:
Pictures of famous waterfalls :

Question 9.
Gorges are suitable for construction of dams- can you tell why this is so? (Text Book Page No. 21)
Answer:

• Gorges are narrow valleys with steep sides.
• A gorge is almost equal in width at its top as well as its bottom.
• They are suitable for the construction of massive reservoirs.
• The natural valleys formed by the gorges are built up with hard rock.
• The valleys with its steep sides, extensive rocky floors form the natural reservoirs for the dams.
• Constructing the dams at gorges is less expensive because a little concrete work is needed to form the reservoirs.
• In these vast and massive reservoirs a lot of water can be stored.
• Gorges are flood proof. They prevent floods.
• The waterfalls that falls down from great heights into the gorges can rotate large turbines and generate hydroelectricity in large quantities.
• Thus gorges are suitable for the construction of dams.

Question 10.
You have read about mining of minerals like baryte or coal. In what ways do you think does mining affects the lithosphere, hydrosphere and atmosphere? (Text Book Page No. 14)
Answer:

• Mining disturbs and removes the rocks, ores and minerals in the lithosphere leaving huge gaping holes in the earth.
• The mine tailings are piled up in large mounds on the surface of the earth.
• Mining waste when washed into the water ways pollutes the hydrosphere.
• Mining causes air pollution to the atmosphere in several ways.
• The mine might also release poisonous gases that were trapped below the surface.
• Mining affects the biosphere by affecting the other three spheres in an indirect way.

Question 11.
Human beings consume a lot of medicines like anti-biotics to cure sickness. How do you think does it affect the lithosphere, hydrosphere and biosphere? (Text Book Page No. 14)
Answer:

• More than 10,000 tonnes of anti biotics are consumed in Europe each year.
• 30%-60% of them passthrough animals and humans unchanged and reach the ocean.
• These antibiotics can affect the marine ecosystems over a long period, with detrimental effects on natural marine communities of bacteria.
• The presence of antibiotics in the marine environment is worrying as it can reach to humans through the consumption of sea food and fish.
• The marine sediments affected by the antibiotics metabolise both nitrogen and carbon which are linked to both eutrophication and climate problems.

Question 12.
What are the dangers of living on the flood plains? (Text Book Page No. 23)
Answer:

• Flood plains are flood prone areas.
• Massive damage can occur during floods in flood plains.
• Homes, automobiles, buildings, historical monuments, graves, sewer systems, bridges and countless other infrastructure can be destroyed.
• Road ways often suffer. High flooding often claims the lives of drowning victims.
• In flood plains during floods there will be lack of clean drinking water which causes illness and epidemics to spread.
• Thus there are a lot of dangers of living on the flood plains.

Question 13.
Locate the Himalayas, Andes and Rockies mountains. Why were they formed in those locations? Suggest reasons. (Text Book Page No. 17)
Answer:

1) Himalayas
2) Rockies mountains
3) Andes mountains

Reasons:

1. Fold mountains are mountains formed from the folding of the earth’s crust.
2. The Himalayas, the Andes and the Rockies are fold mountains.
3. These fold mountains are formed when two plates move together.
4. The Himalayan mountains were formed by the process of Indian plate pushing the Eurasian plate.
5. The forces of plate tectonics are responsible for the formation of Andes.
6. The Nazce plate and a part of the Antarctica plate have been subducting beneath the South American plate.
7. The Rockey mountains took shape during an intense period of plate tectonic activity that resulted in much of the rugged landscape of the Western North America.
8. The Laramide Orogeny was responsible for raising the Rocky mountains.

Question 14.
You may have noticed that many of the ‘scientific’ terms use Greek words. Why do you think do they use Greek words? Discuss with your teacher. (Text Book Page No. 14)
Answer:
In his communication a scientist is mainly concerned with exact and logical expression of that which he wishes to pass on to another. His purpose is to inform as clearly as possible. Each of his words must have a precise meaning and one meaning only so that there is no risk of confusion or ambiguity. The meanings of many ordinary words of our language are not single and precise. The use of words which are ‘set apart’ from everyday life also enables the scientist to avoid evoking irrelevant and distorting associations.

In addition to precision of meaning and freedom from associations most scientific words by their form and structure they reveal something of their meanings. Many scientific words are built from simpler word-elements usually of Greek origin. Some words are self-explanatory if the Greek roots are known.

Scientific language to be efficient must be universally intelligible. The classical language Greek is so fundamental to the civilised world. The words constructed from this language can easily be learnt to be translated.

So scientific terms use Greek words.

Question 14.
Are all rocks on the earth formed in the mid-ocean ridges? (Text Book Page No. 17)
Answer:
No. All the rocks on the earth are not formed in the mid-ocean ridges. Only ocean rocks or crust are formed of the mid-ocean ridges. These are formed by lava rising up from the mantle. The eruptions on the ridges create new ocean floor made of basalt rocks, which then spreads laterally from the ridge. The first order landforms such as oceans and continents are formed at the time when the hot earth was cooling. While the earth’s interior continued to cool, it contracted and the outer crust wrinkled forming ridges i.e., mountains and basins i.e., oceans. The second order landforms such as plains, plateaus and mountains are formed as a result of the internal processes of the earth. The third order landforms such as carved mountains, valleys, deltas, sand dunes are formed as a result of the shaping of the land forms by wind, water.

Question 15.
Why do you think we don’t feel any of these mighty changes taking place on the earth? Is it because they don’t affect us? Do you think these changes affect us at all? (Text Book Page No. 17)
Answer:

• Two kinds of changes take place in the Lithosphere – first the very slow movements leading to the formation of the crust, movement of the continental plates and their eventual return to the mantle.
• Since these geophysical changes occur over thousands and even millions of years we don’t feel any of these changes.
• Secondly the sudden and dramatic eruption of volcanoes and earthquakes.
• The sudden movements can be destructive and cause much damage. At the same time they also lead to changes in landforms.

Question 16.
Compare the action of the river in the mountains and in the plains. In what ways are they similar and different?
Answer:
Similarities :

1. They carry something when they flow across the two landforms.
2. They have streams in both the areas.
3. They change the surface of the earth.

Differences

In the mountains	In the plains
1. Rivers originate in mountains.	1. Rivers run and flow across the plains.
2. They flow very fast.	2. They flow slowly.
3. They carry the rocks.	3. They deposit the sediments here.
4. They form gorges and canyons here.	4. They form deltas here.

From the mountains to delta, a river does not just flow – it changes the surface of the earth.

It cuts rocks, moves boulders, and deposits sediments.
It constantly attempts to carve away all the mountains in its path.

The goal of the river is to create a wide, flat valley which it can flow smoothly towards the ocean.

That is the relation between the mountains and plains.

Question 17.
Why is a flood plain more suited to human habitation compared to mountains? (Text Book Page No. 23)
Answer:
Disadvantages of mountains :

1. High elevation on mountains produces colder climates than at sea level.
2. These colder climates strongly affect the human habitation.
3. Climate of mountains to be used less for agriculture.
4. Abundant water supply.
5. Fertile land – rich for farming and agriculture.
6. Easy to develop than hilly regions.
7. Flood water can be stored temporarily.
8. Many civilizations are flourished on the banks of the rivers.
   These are all more suited to human habitation compared to mountains.

Question 18.
Recall the life of people living in the hills or flood plains that you may have read of. (Text Book Page No. 23)
Answer:
Bison hills are spread in both Bhadradri Kothagudem and W. Godavari districts along either banks of the river Godavari. Many tribal communities live in the hill tracts of this region with their own special life.

These tribals live in small habitations – about 5 to 10 hutments in one place. The habitations are far from each other.

Konda Reddys grow crops in a distinct way called Podu. When rains arrive in June they dibble seeds with the help of digging seeds.

Except for a few months during and after harvest, Konda Reddy women and children are engaged in collection of edible forest produce for subsistence.

There are no rivers or wells in this area. They fetch water from natural springs.

These hill tribes are very few in number but they follow a pattern of life which is very ancient.

SCERT AP Board 9th Class Social Solutions 1st Lesson Our Earth Textbook Questions and Answers.

AP State Syllabus 9th Class Social Studies Solutions 1st Lesson Our Earth

9th Class Social Studies 1st Lesson Our Earth Textbook Questions and Answers

Improve Your Learning

Question 1.
Look at the map of India in an Atlas and identify latitude and longitude for the following places.
a) Kanyakumari ………………. and ………………. .
b) Imohal ………………. and ………………. .
c) Jaisalmer ………………. and ………………. .
d) Pune ………………. and ………………. .
e) Patna ………………. and ………………. .
Answer:
a) Kanyakumari : 77°36′ E longitude and 8°35′ N latitude
b) Imphal : 93°58′ E longitude and 24°44′ N latitude
c) Jaisalmer : 26°55′ N latitude and 70°54′ E longitude
d) Pune : 18°32′ N latitude and 73°52’E longitude
e) Patna : 27°34′ N latitude and 81°46′ E longitude

Question 2.
Identify the words that match with Latitude and Longitude (parallel lines, vertical lines, horizontal lines)
Answer:
Latitudes are horizontal and parallel lines. Longitudes are vertical lines.

Question 3.
Look at the world map of time zones in the Text page 13.
a) If you travel from Vijayawada to Paris to which time zone are you moving?
b) If you are travelling from Hyderabad to Tokyo which time zone are you moving? ……………………… .
Answer:
a) – 5.30 hrs time zone
b) – 3.30 hrs time zone.

Question 4.
Why is it difficult to study the formation of the earth and its structure?
Answer:
Earth formed around 4.54 billion years ago by accretion from the solar nebula. Nearly all branches of natural science have contributed to the understanding of the main events of the earth’s past. The age of the earth is approximately one-third of the age of the universe. Biological and geographical change has been constantly occurring on our planet since the time of its formation. The process of plate tectonics has played a major role in the shaping of earth’s oceans and continents as well as the life on it.

It took us years of scientific investigation and analysis of data to form an understanding of the interiors of the earth. The main reason for this is that even the deepest mines we have dug do not go beyond a few kilometers under the surface while the radius or the distance to the centre of the earth is over 6000 kilometers.

Thus it is very difficult to study the formation of the earth and its structure.

Question 5.
Read the paragraph under the heading of “Internal structure of the earth” and answer the question.

Internal Structure of the Earth : Let us look at the internal structure of the Earth we live on. We can see the continuity from the early days of the formation of the earth as we try to look deep inside the Earth! It took us years of scientific investigation and analysis of data to form an understanding of the interior of the Earth. The main reason for this is that even the deepest mines we have dug do not go beyond a few kilometres under the surface while the radius or the distance to the centre of the earth is over 6000 kilometres!

How can you say the earth is still very active?
Answer:

• The matter deep inside the mantle shoots up through volcanoes and fissures on ocean floors.
• In many regions on the earth part of the earth’s crust enters into the mantle and once again becomes molten.
• The crust is still being changed by earthquakes, volcanoes, subduction of land and rise of mountains due to the processes happening deep down the earth.
• This constant process of formation and destruction of the earth’s crust explains the fact that the earth is still very active.

Question 6.
What is a grid and how does it help us?
(OR)
Write any two uses of the ‘Grid system’ located on the globe.
Answer:
Grid : A grid is a sqaure or a rectangle that is formed between when two latitudes and longitudes out across each other. In other words the network of latitudes and longitudes drawn on the globe is called a ‘grid’.

Uses of grid:
1. Network of latitudes and longitudes is called a Grid.

2. Uses of a grid :
a) To locate a place
b) How hot or cold it would be there,
c) To know the time.

Question 7.
Differentiate between
a) Local and Standard time
b) Equator and Prime meridian.
Answer:
a) Difference between Local and Standard time :

Local Time	Standard Time
1) The time of a place when the mid day sun is over head is called local time.	1) The local time of the standard meridian of a country is called a standard time.
2) It changes from place to place.	2) It remains same for that particular country.
3) The place on the same longitude has the same local time.	3) The place on the same longitude has the different standard time.

Example: If the 1ST is 12.00 noon, the local of Mumbai is 39 minutes – 1ST = 11.21 minutes a.m.
Since Mumbai is on 72°82′ east longitudes, it is 9°45′ behind the 82°30′. Thus the local time of Mumbai is 9.45 x 4 = 38 minutes.

b) Differences between Equator and Prime meridian :

Equator	Prime meridian
1) Equator is 0° latitude.	1) Prime meridian is 0° longitude.
2) Equator divides the earth into parts, i.e. Northern hemisphere and Southern hemisphere.	2) The Prime meridian divides the earth into two equal parts i.e., Eastern hemisphere and the Western hemisphere.
3) Equator is a circle.	3) Prime meridian is a semi-circle.
4) It is an imaginary line that runs east and west around the exact middle of the globe. (A horizontal line)	4) It is an imaginary line running from pole to pole and passing through Greenwich, England. (A vertical line)

Question 8.
If every state follows its local time then what problems will rise?
Answer:
If every state follows4ts local time, a lot of serious problems would rise. Some of them are being discussed hereunder.

1. At the time of national calamities and disasters, it is very difficult for the national government to make necessary emergency announcement.
2. At the time of wars and national emergency, it is very difficult for the national government to alert all the defensive forces stationed in all the state capitals and the naval forces of all the coastal states.
3. It is very difficult for Televisions and Radios to follow a single schedule to broadcast their programmes.
4. Railways faces a difficult problem in preparing a timetable for its trains that travel through many states.

Question 9.
With the help of your teachers find out the standard meridian of given countries.
1. Nepal
2. Pakistan
3. Bangladesh
4. England
5. Malasiya
6. Japan
Answer:
1. Nepal : 88°45’East is the Standard Time Meridian of Nepal
2. Pakistan : 74°22′ East .
3. Bangladesh : 90°24′ East
4. England : 0°07′ West
5. Malaysia : 100° East
6. Japan : 90° East

Question 10.
Make a thought provoking poster on the earth’s protection.
Answer:

9th Class Social Studies 1st Lesson Our Earth InText Questions and Answers

Question 1.
Tick the factors which cause the formation of seasons on the earth : (Text Book Page No. 3)
a) Daily rotation of the earth on its axis.
b) Monthly movement of the Moon around the Earth.
c) Rotation of the Sun on its axis.
d) Revolution of the Earth around the Sun.
e) Tilt of Earth’s axis of rotation to its orbital plane.
f) Spherical shape of the Earth.
g) Earth’s distance from Sun during the annual revolution.
Answer:
d) (✓)
e) (✓)
g) (✓)

Question 2.
We cannot hope to travel to the mantle to study it. But we can study substances from the mantle. Can you tell what these substances would be and how we can get them? (Text Book Page No. 5)
Answer:
1) The thickness of the mantle is 100 – 2900 kms. So we cannot hope to travel to the mantle to study it.
2) Interestingly the matter from the deep inside the mantle shoots up through volcanoes and fissures on ocean floors and cools down to form the earth’s crust.
3) Thus by studying the lava or magma or the substances brought up through the fissures, we can study the substances from the mantle.

Question 3.
When it is 12 noon in Greenwich (0°), what is the local time at: (Text Book Page No. 12)
a) Mumbai (73° E)
b) Chicago (87°30′ W)
c) Sydney (151° E)
Answer:
a) Mumbai (73° E) :
Local time at Mumbai is : 73 × 4 = 292 minutes, i.e. 4 hours 52 minutes. That means the local time at Mumbai is 4 hours 52 minutes after 12 noon i.e., 12.00 + 4.52 = 4.52 p.m.

b) Chicago (87°30′ W):
Local time at Chicago is : 87°30′ × 4 = 350 minutes, i.e. 6 hours 50 minutes. That means the local time at Chicago is 6 hours 50 minutes less than 12.00 noon at Greenwich. i.e. 12.00 – 6.50 = 5.10 a.m.

c) Sydney (151° E): Local time at Sydney is 151° × 4 = 604 minutes, i.e. 10 hours 4 minutes before Greenwich time.
That means the local time at Sydney is 12.00 + 10.04 = 10.04 p.m

Question 4.
Why do you think people today are curious to know about the secrets of distant stars and galaxies and the beginning of the universe? (Text Book Page No. 2)
Answer:
Today people are curious to know about the secrets of the distant stars and galaxies and the beginning of the universe
a) to understand the stars that shine there.
b) to understand the sun, the moon and the planets which keep moving across the sky.
c) to understand what are these and in what way they are related to us and how they affect us.
d) to know how they move and work.
e) to know whether there is any life on any other planet.

Question 5.
Swathi works for a call centre in Hyderabad. Her clients are in the U.S.A. She answers clients’ questions about the computer problems. She always works during the night. Why is this? Use geography to find out! (Text Book Page No. 12)
Answer:
Indian Standard Time is the time observed in India. Its time offset is UTC + 5.30.
United Standard Time is the Central Standard Time. Its time is GMT – 6.00. Thus there is a difference of 11½ hours between Indian Standard Time and American Standard Time. Thus if it is day time in America, in India it is night time. If an American client asks Swathi a question at 11 am in America, Swathi has to answer the same at 10.30 p.m the same day. Thus Swathi should always work at night to answer his clients from the U.S.A.

Question 6.
In earlier classes we have studied about hemisphere. Let us revise it in the image below. (Text Book Page No. 8)

With the help of the above maps complete the following table.

Hemisphere	Continents
Northern hemisphere
Western hemisphere
Southern hemisphere
Eastern hemisphere

Answer:

Hemisphere	Continents
Northern hemisphere	Asia, Europe, North America
Western hemisphere	North America, South America, Antarctica
Southern hemisphere	South America, Africa, Antarctica, Australia
Eastern hemisphere	Asia, Africa, Australia, Antarctica, Europe

Question 7.
Look at the following pictures. (Text Book Page No. 6)

Now answer the following questions.
1. Look carefully at the map of the world, do you find some continents looking as if they are two pieces of a jigsaw puzzle? Name those continents. (Text Book Page No. 7)
Answer:
By observing the maps of the world from 220 million years ago up to the present world, we can find the following continents look as if they are two pieces of jigsaw puzzle. They are :
1) North America and North West Africa.
2) South America and Western Africa.
3) Nothern Africa and Eurasia.
4) Eastern Africa and India.
5) South Eastern Africa and Antarctica.
6) Antarctica and Australia.

2. In which direction Australia is moving?
Answer:
Australia is moving in eastern direction.

3. In which direction India is moving?
Answer:
India is moving in northern direction.

Question 8.
Look at the following map. (Text Book Page No. 12)

Using your Atlas, find out how many standard time zones these countries have :
a) U.S.A
b) Australia
c) Russia
d) Japan
e) Zimbabwe and
f) Chile.
Answer:
a) U.S.A :
The United States uses nine standard time zones. From east to west they are Atlantic Standard Time, Eastern Standard Time, Central Standard Time, Mountain Standard Time, Pacific Standard Time, Alaskan Standard Time, Hawai – Aleutian Standard time, Samoa Standard Time and Chamorro Standard Time.

b) Australia :
Australia uses three standard time zones.
a) Australia Eastern Standard Time (GMT + 10)
b) Australia Central Standard Time (GMT + 9½)
a) Australia Western Standard Time (GMT + 8)

c) Russia :
There are 9 time zones in Russia.
a) Kaliningrad Time – UTC + 3
b) Moscow Time – UTC + 4
c) Yaketerinburg Time – UTC + 6
d) Omsk Time – UTC + 7
e) Krasnoyarsk Time – UTC + 8
f) Irkutsk Time – UTC + 9
g) Yakutsk Time – UTC + 10
h) Vladivostok Time – UTC + 11
i) Magadan Time – UTC + 12

d) Japan :
Japan Standard Time – UTC + 9

e) Zimbabwe :
Zimbabwe uses Central Africa Time zone : UTC + 2h standard time

f) Chile :
Since Chile uses daylight saving time, in total 4 time zones are used.

Question 9.
Initially people thought that the earth was in the centre of the universe and human beings the most important creation. What difference does it make to us to know that we are a small insignificant speck in this vast universe? (Text Book Page No. 2)
Answer:
The earth we live on seems big and very important to us. But in the universe as a whole, it is tiny and very insignificant speck of rock. To put things into perspective earth is just a small planet in the solar system, part of a family of bodies that circle round the sun. The sun is just one of billions of stars that makes up our galaxy, and this galaxy is just one of billions that make up a universe bigger than most of us can imagine.

Question 10.
Do you think the Earth was created suddenly or do you think it was formed by long drawn and complex processes? (Text Book Page No. 4)
Answer:
The Earth began to form around four and a half billion years ago. The earth has reached its present form through several phases but not created suddenly.

• It began as a ball of swirling dust and clouds and passed through a molten stage.
• The molten Earth was very hot and was constantly bombarded by massive rocks and other materials from the space. In this way the size of the earth grew.
• When the earth was so hot and in liquid form the heavier particles went to the bottom and formed core and the mantle.
• The lighter particles cooled at the top and formed the crust.
• While the earth’s interior was cooling, it contracted and outer crust wrinkled forming ridges (i.e., mountains) and basins (i.e., oceans)
• It took a long time for the air we breathe to develop.
  Thus we can say that the earth was not created suddenly but formed through several phases.

Question 11.
Some people believe that our being on this earth is the result of a series of fortuitous accidents – it is quite possible that there may not have been any life on the earth. Do you agree? Give your reasons. (Text Book Page No 4)
Answer:
Yes, the earth’s creatures have evolved through a series of contingent and fortuitous events.
1. Our earth is just the right distance from the sun to have a stable orbit. Our orbit keeps us from getting too hot or too cold to survive. Any closer we’d burn up, any farther away we’d freeze to death.

2. Our earth is perfect in both size and mass. Mass is critically important to the formation of an atmosphere. If the earth’s mass were less dense, an atmosphere could not have formed and remained. If it were more dense, the atmosphere would have been uninhabitable.

3. Our earth has just the right mix of the 27 elements needed for life, including carbon, oxygen, nitrogen, phosphorous, potassium, iron, sodium, and copper.

4. Our earth has just right amount of water in the proper ratios of liquid, solid, and gas.

A little more and the continents would probably be totally overrun with water and literally, drown. Any less and the temperature of the earth would probably be too hot making life unbearable here.

Thus we can say that our being on this earth is the result of fortuitous accidents.

AP State Board Syllabus AP SSC 10th Class Chemistry Solutions Chapter 4 Acids, Bases and Salts Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Chemistry Solutions 4th Lesson Acids, Bases and Salts

10th Class Chemistry 4th Lesson Acids, Bases and Salts Textbook Questions and Answers

Review of Your Previous Knowledge

Question 1.
Which property do you think of while suggesting the remedy from a problem of acidity?
Answer:
Neutralization Property. Antacid tablets neutralise acidity.

Improve your learning

Question 1.
Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11,7 and 9 respectively, which solution is : (AS1)
a) neutral
b) strongly alkaline
c) strongly acidic
d) weakly acidic
e) weakly alkaline
Arrange the pH in increasing order of hydrogen ion concentration.
Answer:
Solution – pH Value
A → 4
B → 1
C → 11
D → 7
E → 9
a) Solution ‘D’ is neutral
b) Solution ‘C’ is strongly alkaline
c) Solution ‘B’ is strongly acidic
d) Solution ‘A’ is weakly acidic
e) Solution ‘E1 is weakly alkaline
∴ Increasing order of Hydrogen ion concentration : C < E < D < A < B.

Question 2.
What is a neutralization reaction? Give two examples. (AS1)
Answer:
Neutralization reaction : When acid reacts with base, forms its salt and water. This reaction is called a neutralization reaction.
Examples :

Equation: HCl + NaOH → NaCl + H₂O
ii) Acetic Acid + Sodium Hydroxide → Sodium Acetate + Water
Equation : CH₃COOH + NaOH → CH₃COONa + H₂O
Formula : Acid + Base > Salt + Water

Question 3.
What happens when an acid or base is mixed with water? (AS1)
Answer:
When an acid or base is mixed with water it changes into dilute acid or dilute base.
(OR)
Dilute acid or dilute base will be formed when an acid or base is mixed with water. Mixing an acid or base with water results in decrease in the concentration of ions (H30+/ OH-) per unit volume. Such a process is called dilution and the acid or base is said to be diluted.

Question 4.
Why does tooth decay start when the pH of mouth is lower than 5.5? (AS1)
(OR)
Does the pH change tooth decay? Explain.
Answer:

1. Tooth enamel is the hardest substance in the body.
2.  It doesn’t dissolve in water but corroded when the pH in the mouth is below 5.5.
3. It happens due to the bacteria which produce acids by degradation of sugar and food particles remaining in the mouth.

Question 5.
Why does not distilled water conduct electricit? (AS2)
Answer:

1. Distilled water does not contain impurities.
2. It is also extremely weak electrolyte.
3. So it does not dissociate into ions.
4. It does not have charge carriers.
5. Because of that it does not conduct electricity.

Question 6.
Dry hydrogen chloride gas does not turn blue litmus to red whereas hydrochloric acid does. Why? (AS1)
Answer:
1. Dry hydrogen chloride gas is not an acid. Because it does not produce H⁺_(aq) ions. Hence it can’t turn blue litmus into red.
2. Hydrochloric acid is an aqueous solution. So it can produce H⁺_(aq) ions. Hence it can turn blue litmus into red.

Question 7.
Why pure acetic acid does not conduct electricity? (AS1)
Answer:
The reasons for pure acetic acid does not conduct electricity are :
i) Acetic acid is a weak acid.
ii) It gives fewer H₃O⁺ ions.

Question 8.
A milkman adds a very small amount of baking soda to fresh milk. (AS2)
a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
Answer:
1. By adding a very small amount of baking soda to fresh milk, the milkman keeps the milk unspoiled for little more time than usual time.
2. As the pH value increases the milk turns to slightly alkaline.

b) Why does this milk take a long time to set as curd?
Answer:

1. Curd form from the milk by the action of Lactic acid produced by bacteria in the milk.
2. If milk man add Baking soda (NaHCO₃) to the milk it neutralise acid, which is produced by the bacteria.
3. Excess acid is required to change the milk as curd.
4.  It takes long time.

Question 9.
Plaster of Paris should be stored in a moisture-proof container. Explain why? (AS2)
Answer:
Storing of Plaster of Paris :

1. Plaster of Paris is a white powder.
2. It easily absorbs water in air and forms hard gypsum.
3. So, it should be stored in a moisture-proof container.

Question 10.
Fresh milk has a pH of 6. Explain why the pH changes as it turns into curd.
Answer:
1. Fresh milk has a pH of 6. Hence it is a weak acid.
2. To turn the milk as curd, we have to add yeast in the form of some curd. The fermentation takes place during this process and lactose changes in lactic acid and the pH decreases as milk sets as curd.

Question 11.
Compounds such as alcohols and glucose contain hydrogen but are not categorized as acids. Describe an activity to prove it. (AS3)
(OR) (Activity – 7)
Write an activity to show that the solutions of compounds like alcohol and glucose do not show acidic character even though they are having Hydrogen.
(OR)
Write an activity which proves acids are good conductors of electricity.
(OR)
The acidity of acids is attributed to the H+ ions produced by them in solution explain the above statement with an activity.
List out the material for the experiment to investigate whether all compounds containing Hydrogen are acids or not and write the experimental procedure.
Answer:
List of the material required :

1. Glucose
2. Alcohol
3. Dil. HCl
4. Dil-H₂SO₄
5. Beaker
6. Connecting wires
7. 230 voltage AC supply
8. Bulb
9. Graphite rods.

Procedure :

1. Prepare glucose, alcohol, hydrochloric acid and sulphuric acid solutions.
2. Connect two different coloured electrical wires to graphite rods separately as shown in figure.
3. Connect free ends of the wire to 230 volts AC plug.
4. Complete the circuit as shown in the figure by connecting a bulb to one of the wires.
5. Now pour some dilute HCl in the beaker and switch on the current.

Observation :
The bulb starts glowing.

Repetition:
Repeat activity with dilute sulphuric acid, glucose and alcohol solutions separately.

Observation :

1. We will notice that the bulb glows only in acid solutions.
2. But the bulb does not glow in glucose and alcohol solutions.

Result:

1. Glowing of bulb indicates that there is flow of electric current through the solution.
2. Acid solutions have ions and the movement of these ions in solution helps for flow of electric current through the solution.

Conclusion :

1. The positive ion (cation) present in HCl solution is H⁺.
2. This suggests that acids produce hydrogen ions H⁺ in solution, which are, responsible for their acidic properties.
3. In glucose and alcohol solution the bulb did not glow indicating the absence of H⁺ ions in these solutions.
4. The acidity of acids is attributed to the H⁺ ions produced by them in solutions.

Question 12.
What is meant by “water of crystallization” of a substance? Describe an activity to show the water of crystallisation. (Activity – 16) (AS3)
Answer:
Water of Crystallization : Water of crystallization is the fixed number of water molecules present in one formula unit of a salt in its crystaline form.
Ex : CuSO₄ • 5H₂O.
It means that five water molecules are present in one formula unit of copper sulphate.

Activity to show the water of crystallization :

1. Take a few crystals of copper sulphate in a dry test tube and heat the test tube.
2. We observe water droplets on the walls of the test tube and salt turns white.
3. Add 2 – 3 drops of water on the sample of copper sulphate obtained after heating.
4. We observe, the blue colour of copper sulphate crystals is restored.

Reason :
1. In the above activity copper sulphate crystals which seem to be dry contain the water of crystallization, when these crystals are heated, water present in crystals is evaporated and the salt turns white.

2. When the crystals are moistened with water, the blue colour reappears.
Removing water of crystallization

Question 13.
Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid is added to test tube A, while acetic acid is added to test tube B. Amount and concentration of both the acids are same. In which test tube will the fizzing occur more vigorously and why? (AS4)
Answer:
1. The volatility of acetic acid (CH₃COOH) is more than that of hydrochloric acid.
2. But HCl solution has more strength than acetic acid.
3. Hence magnesium ribbon in test tube A will react more vigorously than in B.
4. So fizzing occurs more vigorously in test tube ‘A’.

Question 14.
Draw a neat diagram showing acid solution in water conducts electricity. (AS5)
(OR)
Draw a neat diagram which shows acids contains H⁺ ions.
(OR)
Draw a neat diagram showing how does dilute HCl solution conduct electricity.
Answer:

Question 15.
How do you prepare your own indicator using beetroot ? Explain. (AS5)
Aim : To prepare own indicator.
Materials required :
1) Beetroots-2 or 3
2) Knife
3) Bowls
4) Water
5) Spoon
6) Mixy
7) Orange juice

Procedure:
1) Take the beetroots and peel them with the help of a knife. (Firstly wash them).
2) Chop them into pieces.
3) Put those pieces into a mixy jar and make a paste.
4) Add some water to the paste. Now filter this and collect only juice from this.

Observation and Result:
1) Now add 5 to 6 drops of this juice, (beetroot juice (indicator)) to orange juice (5 to 6 drops) and mix it.
2) We can see the colour changes. This indicates the presence of acidic nature in orange juice.

Question 16.
How does the flow of acid rain into a river make the survival of aquatic life in a river difficult? (AS7)
(OR)
What are the harmful effects of acid rain?
Answer:
1) Acid rains are combination of carbonic acid, sulphuric acid and nitric acid with rain water.
2) The pH of acid rain is less than 5.6.
3) Living organisms can survive only in a narrow range of pH change.
4) When acid rain with pH value less than 5.6, flows into rivers, it lowers the pH of river water.
5) Due to less pH, the river water becomes acidic and hence the aquatic life in such rivers becomes difficult.

Question 17.
What is baking powder? How does it make the cake soft and spongy? (AS7)
Answer:
1) Baking Powder:
Baking powder is a mixture of baking soda (NaHCO₃) and a mild edible acid such as tartaric acid. COOH (CHOH)₂ COOH

2) Chemical reaction :
When baking powder is heated or mixed in water, the following reaction takes place.
NaHCO₃ + H⁺ → CO₂ + H₂O + Sodium salt of acid.

3) Carbondioxide produced during the reaction causes bread or cake to rise making them soft and spongy.

Question 18.
Give two important uses of washing soda and baking soda. (AS7)
(OR)
Write the chemical formulae for washing soda and Baking soda and give their uses.
(OR)
Write any four uses of washing soda.
Answer:
Uses of washing soda (Na₂CO₃.10H₂O) :
1) Washing soda (sodium carbonate) is used in glass, soap and paper industries.
2) It is used in the manufacture of sodium compounds such as borax.
3) Sodium carbonate can be used as a cleaning agent for domestic purposes.
4) It is used for removing permanent hardness of water.

Uses of baking soda (NaHCO₃ 10H₂O) :
1) Baking soda (Sodium hydrogen carbonate) is used for faster cooking.
2) Baking powder (a mixture of baking soda and a mild acid) is used in preparation of cakes.
3) Sodium hydrogen carbonate is also an ingredient in antacids.
4) It is also used in soda – acid, fire extinguishers.
5) It acts as a mild antiseptic.

Fill in the Blanks

1. i) ………………….. taste is a characteristic property of all acids in aqueous solution.
ii) Acids react with some metals to produce ………………….. gas.
iii) Because aqueous acid solutions conduct electricity, they are identified as …………………..
iv) Acids react with bases to produce a ………………….. and water.
v) Acids turn methyle orange into ………………….. colour.
Answer:
1. i) Sour
ii) hydrogen
iii) electrolytes or conductors
iv) salt
v) red

2. i) Bases tend to taste ………………….. and feel ………………….. .
ii) Like acids, aqueous basic solutions conduct ………………….., and are identified as ………………….. .
iii) Bases react with ………………….. to produce a salt and
iv) Bases turn phenophthalein into ………………….. colour.
Answer:
2. i) bitter, soapy (slippery) to touch
ii) electricity, electrolytes
iii) acids, water
iv) pink

Match the following :

a) Plaster of Paris	1) CaOCl2
b) Gypsum	2) NaHCO3
c) Bleaching powder	3) Na2CO3
d) Baking soda	4) CaSO4.½H2O
e) Washing soda	5) CaSO4.2H2O

Answer:
3. a – 4,
b – 5,
c – 1,
d – 2,
e – 3.

Multiple Choice Questions

1. The colour of methyl orange indicator in acidic medium is
A) yellow
B) green
C) orange
D) red
Answer:
D) red

2. The colour of phenolphthalein indicator in basic solution is
A) yellow
B) green
C) pink
D) orange
Answer:
C) pink

3. Colour of methyl orange in alkali conditions
A) orange
B) yellow
C) red
D) blue
Answer:
B) yellow

4. A solution turns red litmus blue, its pH is likely to be
A) 1
B) 4
C) 5
D) 10
(OR)
If a solution converts red litmus into blue colour, then its pH value is …………….. .
A) 1
B) 4
C) 5
D) 10
Answer:
D) 10

5. A solution reacts with crushed egg-shells to give a gas that turns lime-water milky, the solution contains …………….. .
A) NaCl
B) HCl
C) LiCl
D) KCl
Answer:
B) HCl

6. If a base dissolves in water, by what name is it better known?
A) neutralization
B) basic
C) acid
D) alkali
Answer:
D) alkali

7. Which of the following substances when mixed together will produce table salt?
A) Sodium thiosulphate and sulphur dioxide
B) Hydrochloric acid and sodium hydroxide
C) Chlorine and oxygen
D) Nitric acid and sodium hydrogen carbonate
Answer:
B) Hydrochloric acid and sodium hydroxide

8. What colour would hydrochloric acid (pH = 1) turn universal indicator?
A) Orange
B) Purple
C) Yellow
D) Red
Answer:
D) Red

9. Which one of the following types of medicines is used for treating indigestion?
A) antibiotic
B) analgesic
C) antacid
D) antiseptic
Answer:
C) antacid

10. What gas is produced when magnesium is made to react with hydrochloric acid?
A) hydrogen
B) oxygen
C) carbon dioxide
D) no gas is produced
Answer:
A) hydrogen

11. Which of the following is the most accurate way of showing neutralization?
A) Acid + base → acid-base solution
B) Acid + base → salt + water
C) Acid + base → sodium chloride + hydrogen
D) Acid + base → neutral solution
Answer:
B) Acid + base → salt + water

10th Class Chemistry 1st Lesson Acids, Bases and Salts InText Questions and Answers

10th Class Chemistry Textbook Page No. 25

Question 1.
Is the substance present in antacid tablet acidic or basic?
A. The substance present in antacid tablet is basic.

Question 2.
What type of reaction takes place in stomach when an antacid tablet is consumed?
mrearx
A. Neutralization reaction takes place in stomach when an antacid tablet is consumed.

10th Class Chemistry Textbook Page No. 26

Question 3.
You are provided with three test tubes containing distilled water, an acid and a base solution respectively. If you are given only blue litmus paper, how do you identify the contents of each test tube?
Answer:
I know that acid turns blue litmus to red. With the help of this test I can find the acid. Distilled water and base don’t do so. Thus I identify each.

Question 4.
Which gas is usually liberated when an acid reacts with a metal? How will you test for the presence of this gas?
Answer:
Usually acids generate hydrogen gas on reacting with metals.

Test: When a burning splinder is brought near to the collected gas (H₂), it puts off with a pop sound.
This test proves that the gas is H₂.

Question 5.
A compound of a calcium reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle ; turns lime water milky. Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.
Answer:
Equation is : CaCO₃ + 2 HCl → CaCl₂ + CO₂ + H₂O

10th Class Chemistry Textbook Page No. 30

Question 6.
Why do HCl, HNO₂ etc. show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?
Answer:
HCl, HNO₃, etc. show acidic characters in aqueous solutions as they liberate H⁺ ions. But alcohol and glucose don’t liberate H⁺ ions. So, they do not show acidic character.

Question 7.
While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
Answer:
1) If water is added to a concentrated acid, the heat generated may cause the mixture to splash out and cause burns.
2) The glass container may also break due to excessive local heating.

10th Class Chemistry Textbook Page No. 33

Question 8.
What will happen if the pH value of chemicals in our body increases?
Answer:
When pH value of chemicals in our body increases then the body will effect by some problems. They are
1) Digestion problems raise in the stomach.
2) pH changes as the cause of tooth decay.

Question 9.
Why do living organism have narrow pH range?
Answer:
Because increasing acidity is thought to have a range of possibly harmful consequences such as depressing metabolic rate and immune response in some organisms and causing coral bleaching

10th Class Chemistry 4th Lesson Acids, Bases and Salts Activities

Activity – 1

Question 1.
Observe the change in colour in each case and tabulate the results in the table.
Answer:
Procedure:
1) Collect the following samples from the science laboratory ;
i) Hydrochloric acid (HCl)
ii)Sulphuric acid (H₂SO₄)
iii) Nitric acid (HNO₃)
iv) Acetic acid (CH₃COOH)
v) Sodium hydroxide (NaOH)
vi) Calcium hydroxide[Ca(OH)₂]
vii) Magnesium hydroxide [Mg(OH)₂]
viii) Ammonium hydroxide(NH₄OH)
ix) Potassium hydroxide (KOH)
2) Prepare dilute solutions of the respective substances.
3) Take four watch glasses.
4) Put one drop of the first solution in each one of them and test the solution as follows.
i) Dip the blue litmus paper in the first watch glass.
ii) Dip the red litmus paper in the second watch glass.
iii) Add a drop of methyl orange to the third watch glass.
iv) Add a drop of phenolphthalein to the fourth watch glass.

Observation :
Observe the respective colour changes and note down in the chart below.

1. What do you conclude from the observations noted in the above table? (AS1)
Answer:
Conclusion : Acids turn blue litmus to red and bases turn red litmus to blue. Acids turn phenolphthalein to colourless and bases turn pink. Acids turn methyl orange to red and bases turn methyl orange to yellow.

2. Identify the above sample as acidic or basic solution. (AS4)
Answer:
Acids : HCl, H₂SO₄, HNO₃, CH₃COOH.
Bases : NaOH, KOH, Mg(OH)₂, NH₄OH, Ca(OH)₂.

Activity -2

Question 2.
What are Olfactory indicators? Write an activity to prove them.
(OR)
What is the name given to a substance which identifies an acid or base by virtue of smell? Write an activity to prove the fact with an example.
Answer:
Olfactory Indicators : There are some substances whose odour changes in acidic or basic media. These are called olfactory indicators.
Activity :
Aim : To check the olfactory indicator.
Required materials :
1) Onions
2) Knife
3) Plastic bag
4) Clean clothes.

Procedure :
1) Take some onions and finely chop them.
2) Put the chopped onions in a plastic bag along with some clean cloth.
3) Tie up the bag tightly and keep it overnight in the fridge.
4) Then remove onions from fridge and add some base. We observe it loses its smell. Observation : Check the odour of the cloth strips.

Result: It is used as the basic indicator.

LAB ACTIVITY Reaction of Acids with metals

Question 3.
Write an experiment showing the reaction of acids with metals. (AS3)
(OR)
Ramu added acid to active metal then what is the gas which has been liberated. What are the apparatus required to prove the experiment. Write the experimental acitivity.
(OR)
Write the required material and experimental procedure for the experiment, “Hydrochloric acid reacts with ‘Zn’ pieces and liberates H₂“.
Answer:
Aim : To show the reaction of acids with metals.

Required Materials :

1. Test tube
2. Delivery tube
3. Glass trough
4. Candle,
5. Soap water
6. Dil. HCl
7. Zinc granules
8. One holed rubber stopper
9. Retard stand

Experimental procedure :

1. Take some zinc granules in a test tube and arrange the test tube to the retart stand.
2. Fix a delivery tube to the rubber stopper and immerse the second end of the delivery tube into the soap water.
3. Add about 10 m/ of dilute hydrochloric acid to Zn granules and fix rubber stopper to the test tube.
4. Evolved gas forms bubbles in soap water.
5. Bring a lightened candle near to the gas bubbles. We can observe the burning of gas bubble with pop sound.

Result: We can conform that the evolved gas is hydrogen.
Chemical reaction:
Acid + Metal → Salt + Hydrogen
2Hcl_(aq) + Zn_(s) → Zncl_2(aq) + H_2(g)

Additional Experiment :

• Repeat the above experiment with H₂SO₄ and HNO₃.
• We observe the same observation of the HCL experiment.

Conclusion : From the above activities we can conclude that when acid reacts with metal, H₂ gas is evolved.

Activity – 3 Reaction of Bases with metals

Question 4.
Write an activity to show the reaction of bases with metals.
(OR)
Write an activity which proves certain bases produce hydrogen gas when they react with metals.
Answer:
Aim : To show the reaction of bases with metals.

Required Materials :

1. Test tube,
2. Delivery tube
3. Glass trough
4. Candle
5. Soap water
6. Sodium hydroxide (NaOH) Solution
7. Zinc granules
8. One holed rubber stopper

Procedure :

1. Set the apparatus as shown in figure.
2. Take about 10 ml of dilute Sodium hydroxide (NaOH) solution in a test tube.
3. Add a few granules of zinc metal to it.
4. We will observe formation of gas bubbles on the surface of granules.
5. The gas will pass through delivery tube evolved from soap solution as bubbles.
6. Bring burning candle near the gas filled bubble.
7. The gas in the bubble puts off the candle with pop sound.

Result: The evolved gas is hydrogen.

Chemical reaction :
Base + Metal → Salt + Hydrogen

Note : It is better to use cone. NaOH solution for this reaction.

Activity – 4 Reaction of carbonates and metal hydrogen carbonates with Acids

Question 5.
Write an activity to show that all metal carbonates and hydrogen carbonates react with acids to give a corresponding salt. (AS3)
Answer:
Aim : To show that all metal carbonates and hydrogen carbonates react with acids to give a corresponding salt.

Required Materials :

1. Two test tubes
2. Sodium Carbonate (Na₂CO₃)
3. Sodium Hydrogen Carbonate (NaHCO₃)
4. Two holed rubber stopper
5. Thistle funnel
6. Stand
7. Dilute hydrochloric acid
8. Delivery tube
9. Calcium Carbonate (in a test tube)

Procedure :

1. Take a test tube A with 0.5 gm of sodium carbonate.
2. Close the test tube A with two holed rubber cork.
3. Insert a thistle funnel through one hole and insert a delivery tube through the other hole.
4. Pour 2 ml of dilute HC/ to the test tube A.
5. Do the same as above with test tube B with sodium hydrogen carbonate.

Observation :
Carbon dioxide is released from test tube A and B. Passing CO₂ gas through Ca(OH)₂ solution

Chemical Reaction :
Na₂CO_3(s) + 2 HCl_(aq) → 2 NaCl_(aq) + CO_2(g) + H₂O_(l)
Metal Carbonate + Acid → Salt + Carbon dioxide + Water

NaHCO_3(s) + HCl_(aq) → NaCl_(aq) + CO_2(g) + H₂O_(l)
Metal Hydrogen Carbonate + Acid → Salt + Carbon dioxide + Water

Result : All metal carbonates and hydrogen carbonates react with acids to give a corresponding salt.

Activity – 5 Neutralization reaction

Question 6.
Write an activity to find the change of colour in the reaction of an acid with a base (Neutralization) reaction. (AS3)
(OR)
Explain neutralization reaction with an activity.
Answer:
Aim : To test the change of colour in the reaction of an acid with a base.

Required Materials :

1. 2 ml of dilute NaOH (Sodium Hydroxide) solution.
2. Phenolphthalein indicator solution.
3. dilute HCl (Hydrochloric) solution.

Procedure :

1. Take about 2 ml of dilute NaOH solution in a test tube.
2. Add two drops of phenolphthalein indicator solution.

Observation (i) :

1. It turns to red or pink colour.
2. It shows that NaOH is a base.

Experiment (1) : Add dilute HCl solution to the above solution drop by drop.
Observation (ii) : Pink colour disappears due to the reaction of NaOH (base) with HCl (acid).

Experiment (2) : Now add one or two drops of NaOH to the above mixture.
Observation (iii) : Pink colour reappears on adding NaOH.
NaOH + HCl → NaCl + H₂O
base + acid → salt + water
Result: This reaction is called a neutralization reaction.

Activity – 6 Reaction of metallic oxides with acids

Question 7.
Write an activity to show that metal oxide reacts with acid is a neutralization. (AS3)
(OR)
How can you prove metallic acids are basic in nature?
Answer:
1) Take a small amount of copper oxide (CuO) in a beaker.
2) Add dilute HCl slowly while stirring.
3) Copper oxide dissolves in dilute HCl and the solution becomes blueish green colour due to the formation of copper (II) chloride.

Equation : Metal oxide + Acid → Salt + Water
Result: This reaction is same as the reaction of base with acid, (neutralization)

Question 8.
Write an activity to show that non-metallic oxide reacts with base is a neutralization.
Answer:
1) Take a small amount of calcium hydroxide (base).
2) Add CO₂ into it.
3) Salt and water are produced.
Equation : Non-metallic oxide + Base → Salt + Water
Result: It is a neutralization reaction.

Question 9.
Repeat the activity – 7 using alkalis such as sodium hydroxide, calcium hydroxide solutions, etc. instead of acid solutions.
i) Does the bulb glow?
Answer:
Yes, the bulb will glow.

ii) What do you conclude from the results of this activity?
Answer:
Basic solutions are also good conductors of electricity due to released OH^– ions.

iii) What happens to an acid or a base in aqueous solution?
Answer:
Acids produce H⁺ ions and bases produce OH^– ions in aqueous solutions.

iv) Do acids produce ions only in aqueous solution?
Answer:
Yes.

Activity – 8

Question 10.
Do acids produce ions only in aqueous solution? Prove it. (AS3)
(OR)
Acids produce ions only in aqueous solution. Justify your answer with an activity.
Answer:
Procedure :

1. Take about 1.0 g of solid NaCl in a clean and dry test tube.
2. Add some concentrated sulphuric acid to the test tube. .

Observation :

1. A gas comes out of the delivery tube.
2. If we test the gas with dry and wet blue litmus paper, there is no change in colour.

Chemical equation : 2 NaCl_(s) + H₂SO_4(l) > 2 HCl + Na₂SO_4(s)

Conclusion :

1. We can conclude that dry HCl gas (hydrogen chloride) is not an acid.
2. Because we have noticed that there is no change in colour of dry litmus paper.
3. But HCl aqueous solution is an acid because wet blue litmus paper turned into red.

Activity – 9 Reaction of water with acids or bases

Question 11.
Write an activity to show that dissolving of an acid in water is an exothermic process (or) endothermic process. (AS3)
(OR)
What do you observe when water is mixed with acid or base?
Answer:
Experiment :

1. Take 10 ml water in a beaker.
2. Add a few drops of concentrated H₂SO₄ to it and swirl the beaker slowly.
3. Touch the base of the beaker.
4. The base is hot.
5. Do this experiment with other concentrated acids like HCl, HNO₃ Result: This is an exothermic process called dilution.

Activity -10 Strength of acid or base

Question 12.
Write an activity to know whether the acid is strong or weak. (AS3)
Answer:

1. Take dilute HCl in a beaker.
2. Close it with a cardboard and introduce two different colour electrical wires through the holes made on it.
3. Connect a bulb and make the connection as shown in the figure.
4. Do the same replacing dilute HCl with dilute CH₃COOH (acetic acid).

Observation :
The bulb glows brightly in HCl solution, while the bulb’s intensity is low in acetic acid solution.

Result:
More ions are present in HCl solution which is a strong acid than in CH₃COOH solution which is a weak acid.

Activity – 11

Question 13.
Test the pH value of solution given in table. Record your observations. What is the nature of each substance on the basis of your observations?
Answer:

Activity – 12

Question 14.
Write an activity to check the colour change in dilute HCl and antacid solution in addition of methyl orange. (AS3)
Answer:
Procedure :

1. Take dilute HCl in a beaker.
2. Add two to three drops of methyl orange indicator to it.
3. The solution colour turns to red.
4. Now take the same solution and mix antacid tablet powder.

Observation :
Check the colour change.

Result:
The colour of the solution turns to light yellow.

Chemical equation:
2 HCl + Mg(OH)₂ → MgCl₂ + 2H₂O

Activity – 13

Question 15.
How can we test the pH value of the soil? (AS3)
Answer:

1. Take about 2g of soil in a test tube.
2. Add 5 ml water to it.
3. Shake it well.
4. Filter the content.
5. Collect the filtrate in a test tube.
6. Add 2 drops of universal solution to it.
7. Observe the colour.
8. Compare the colour with strip colour on the bottle and find the pH value.
9. In this way we can test the pH of the soil.

Activity – 14

Question 16.
Write the formulae of the following salts and classify them as families based on radicals.
Potassium Sulphate, Sodium Sulphate, Calcium Sulphate, Magnesium Sulphate, Copper Sulphate, Sodium Chloride, Sodium Nitrate, Sodium Carbonate and Ammonium Chloride. (AS4)
Answer:

Name of the Salt	Formula
1. Potassium Sulphate	K2SO4
2. Sodium Sulphate	Na2SO4
3. Calcium Sulphate	CaSO4
4. Magnesium Sulphate	MgSO4
5. Copper Sulphate	CuSO4
6. Sodium Chloride	NaCl
7. Sodium Nitrate	NaNO3
8. Sodium Carbonate	Na2CO3
9. Ammonium Chloride	NH4Cl

Sodium family : Na₂SO₄, NaCl, NaNO₃, Na₂CO₃, etc.
Family of chloride salts : NaCl, NH₄Cl, etc.
Family of sulphate salts : K₂SO₄, Na₂SO₄, CaSO₄, MgSO₄, CuSO₄, etc.
Family of carbonate salts : Na₂CO₃ MgCO₃ CaCO₃, etc.

Question 17.
Identify the acids and bases from which they are obtained. (AS4)
Answer:

Name of the Salt	Parent Acid	Parent Base
1. Potassium Sulphate	Sulphuric Acid	Potassium Hydroxide
2. Sodium Sulphate	Sulphuric Acid	Sodium Hydroxide
3. Calcium Sulphate	Sulphuric Acid	Calcium Carbonate
4. Magnesium Sulphate	Sulphuric Acid	Magnesium Hydroxide
5. Copper Sulphate	Sulphuric Acid	Copper Hydroxide
6. Sodium Chloride	Hydrochloric Acid	Sodium Hydroxide
7. Sodium Nitrate	Nitric Acid	Sodium Hydroxide
8. Sodium Carbonate	Carbonic Acid	Sodium Hydroxide
9. Ammonium Chloride	Hydrochloric Acid	Ammonium Hydroxide

Activity – 15 pH of Salts

Question 18.
Collect the salt samples like sodium chloride, aluminium chloride, copper sulphate, sodium acetate, ammonium chloride, sodium hydrogen carbonate and sodium carbonate. Dissolve them in distilled water. Check the action of these solutions with litmus papers. Find the pH using pH paper (universal indicator. Classify them into acidic, basic or neutral salts. Identify the acid and base used to form the above salts. Record your observations in table. (AS4)
Answer:

Salt	pH	Acid	Base	Neutral
Sodium Chloride	7	–	–	✓
Aluminium Chloride	7	–	–	✓
Copper Sulphate	< 7	✓	–	–
Sodium Acetate	> 7	–	✓	–
Ammonium Chloride	< 7	✓	–	–
Ammonium Chloride	> 7	–	✓	–
Sodium Carbonate	> 7	–	✓	–

 

AP State Board Syllabus AP SSC 10th Class Physics Solutions Chapter 1 Heat Textbook Questions and Answers.

AP State Syllabus SSC 10th Class Physics Solutions 1st Lesson Heat

10th Class Physics 1st Lesson Heat Textbook Questions and Answers

Improve your learning

Question 1.
What would be the final temperature of a mixture of 50 g of water at 20° C temperature and 50 g of water at 40° C temperature? (AS1)
Answer:
In CGS system :
Mass m₁ = 50 g
Higher temperature = T₁ = 40° C
Mass m₂ = 50 g
Lower temperature = T₂ = 20° C

Question 2.
Explain, why dogs pant during hot summer days using the concept of evaporation. (AS1)
(OR)
How do dogs cool their body? Explain by using the process of evaporation.
Answer:

• Dogs pant during hot summer days and get their body cooled. This cooling effect is due to evaporation.
• Evaporation is a surface phenomenon. Temperature of a system falls during evaporation.
• During summer the temperature in the human body increases.
• The temperature of the skin becomes higher and the water in the sweat glands starts evaporating. Since evaporation is a cooling process human body becomes cool.
• Dogs don’t have sweat glands. Their body is covered with hair. They have sweat glands only in their feet.
• So by panting the water on the tongue undergoes evaporation resulting in the cooling of the dog’s body.

Question 3.
Why do we get dew on the surface of a cold soft drink bottle kept in open air? (AS1)
(OR)
Raju observed small droplets of water outside a cold soft drink bottle kept in open air. What is the reason for the formation of droplets?
Answer:

• When cold soft drink bottle is kept in open air, the temperature of surrounding air is higher than the temperature of cold drink bottle.
• Air contains molecules in the form of vapour.
• During the motion of water molecules in air strike the surface of cold drink bottle.
• Then the molecules of air lose their kinetic energy which leads to lower the temperature and they convert into droplets.
• So dew is formed on the surface of cold soft drink bottle.

Question 4.
Write the differences between evaporation and boiling. (AS1)
(OR)
Sita observed decrease in quantity of spirit kept in a vessel placed in open air. Whereas Ramu observed formation of bubbles on a water surface when it is heated. What are those two processes? Distinguish between those two processes.
Answer:

Evaporation	Boiling
1. The process of escaping of molecules from the surface of a liquid at any temperature is called evaporation.	1. The process in which the liquid phase changes to gaseous phase at constant temperature. This temperature is called boiling point of liquid.
2. Evaporation takes place at any temperature.	2. Boiling takes place at a definite temperature.
3. The temperature of liquid gets down.	3. The temperature of liquids increases up to a constant temperature.
4. The kinetic energy does not change.	4. The kinetic energy of the molecules increases with the increase of temperature.
5. The evaporation depends on surface area, wind, speed, humidity.	5. The boiling depends on atmospheric pressure.
6. It is surface phenomenon.	6. It is bulk phenomenon.
7. Eg : 1) Wet clothes dries. 2) Sea water evaporates to form clouds.	7. Eg : 1) Water boils at 100° C.

Question 5.
Does the surrounding air become warm or cool when vapour phase of H₂O condenses? Explain. (AS1)
Answer:

• Gases have more higher energy than liquids and solids.
• When vapour condenses, it changes from gas to liquid.
• Therefore there is a drop in energy.
• This energy has to go (somewhere) to the surroundings.
• So surrounding air becomes warm when vapour phase of H20 condenses.

Question 6.
Answer these. (AS1)
a) How much energy is transferred when 1 gm of boiling water at 100°C condenses to water at 100°C?
Answer:
CGS system :
Mass of water = m = 1 gm
Latent heat of vapourisation = 540 cal/gm.
The amount of heat energy released when 1 gm of boiling water at 100°C condenses to water at 100°C
Q = mL_vapour = 1 × 540 = 540 cal.

(OR)

In SI system :
Mass of water = m = 1 gm = 1 × 10^-3 kg
Latent heat of vapourisation = 540 cal/gm.
The amount of heat energy released when 1 gm of boiling water at 100°C condenses to water at 100°C
Q = mL_vapour – 1 × 540 = 540 cal.
In SI, Q = 540 × 4.18 = 2257 J.

b) How much energy is transferred when 1 gm of boiling water at 100° C cools to water 0° C?
Answer:
CGS system :
Latent heat of vapourisation = 540 cal/gm
The amount of heat energy released when 1 gm of boiling water at 100°C condenses to water at 100 °C. m = 1 gm.
Q₁ = mL_vapour = 1 × 540 = 540 cal.
The specific heat of water = 1 cal/gm-°C
Difference in temperature = 100-0 = 100°C.
The heat released to cool water to 0°C is
Q₂ = mS∆T = 1 × 1 × 100 = 100 cal.
∴ Total energy released = 540 + 100 = 640 cal.

c) How much energy is released or absorbed when 1 gm of water at 0° C freezes to ice at 0° C?
Answer:
In CGS system :
Mass of water = m = 1 gm
Latent heat of fusion of ice (L) = 80 cal/gm
The energy transferred or released when 1 gm of water at 0° C freezes to ice at 0° C.
Q = mL_freeze = 1 × 80 = 80 Cal.

(OR)

In SI system :
Mass of water = m = 1 gm = \(\frac{1}{1000} \mathrm{~kg}\)
Latent heat of fusion = L = 3.36 × 10⁵ J/kg.
Amount of heat released or transferred when lgm of water at 0°C freezes to ice at 0°C.
Q = mL_fusion = \(\frac{1}{1000} \mathrm{~kg}\) × 3.36 × 10⁵ = 3.36 × 10² = 336J.

(OR)

In CGS system :
Mass of water = m = 1 gm
Latent heat of fusion of ice (L) = 80 cal/gm
The energy transferred or released when 1 gm of water at 0° C freezes to ice at 0°C.
Q = mL_freeze = 1 × 80 – 80 cal.
(Or)
In SI system : In SI, Q = 80 × 4.2 [1 cal = 4.2 J]
Q = 1 x 10^-3 × 3.36 × 10⁵ = 3 36 J.

d) How much energy is released or absorbed when 1 gm of steam at 100°C turns to ice at 0°C?
Answer:
In CGS system :
Mass of water = m = 1 gm
Latent heat of vapourisation = L_vapour = 540 cal/gm
Latent heat of fusion of ice = L_fusion = 80 cal
Specific heat of water = S = 1 cal/gm-0°C
Difference in temperature
∆T = 100 – 0 = 100°C.
The energy transferred when 1 gram of steam at 100°C turns to ice at 0°C
Q = mL_vapour + mS∆T + mL_fusion
= 1 × 540 + 1 × 1 × 100 + 1 × 80 = 540 + 100 + 80 = 720 cal.

(OR)

Mass of water = m = 1 gm = \(\frac{1}{1000} \mathrm{~kg}\)
Latent heat of vapourisation = L_vapour = 2.25 × 10⁶ J/kg
Latent heat of fusion = L_fusion = 3.36 × 10⁵ J/kg
Difference in temperature
∆T = 373 – 273 – 100 K.
Specific heat of water = 4180 J/kg-K
The energy transferred when 1 gram of steam at 100° C turns to ice at 0°C =

(OR)

In CGS system :
Conversion : Steam at 100°C → Water at 100°C → Water at 0°C → Ice at 0°C.
Mass of water = m = 1 gm
Latent heat of vapourisation = L_vapour = 540 cal/gm
Latent heat of fusion of ice = L_fusion = 80 cal
Specific heat of water = S = 1 cal/gm-0°C
Difference in temperature
∆T= 100-0 = 100°C.
The energy transferred when 1 gram of steam at 100°C turns to ice at 0°C
Q = mL_vapour + mS∆T + mL_fusion
= 1 × 540 + 1 × 1 × 100 + 1 × 80
= 540 + 100 + 80 = 720 cal. = 720 × 4.18 = 3009.6 J.

Question 7.
Explain the procedure of finding specific heat of solid experimentally. (AS1)
(OR)
Determination of specific heat of solid experimentally.
(OR)
Ravi wanted to prepare solid with high specific heat to use on cooking utensil. What fool does he need to find the specific heat of aluminium and copper? How should he conduct the experiment?
Answer:
Aim : To find the specific heat of given solid.
Apparatus : Calorimeter, thermometer, stirrer, water, steam heater, wooden box and lead shots.

Procedure:

• Measure the mass of the calorimeter with stirrer = m₁ gm
• Fill water one third volume of calorimeter and measure the mass = m₂ gm.
• At this time initial temperature = T₁.
• Mass of the water = m₂ – m₁ gm.
• Take a few lead shots and place them in steam heater and heat up to 100° C. Let this temperature be T₂.
• Transfer the lead shots into calorimeter and measure the final (or) resultant temperature T₃.
• Mass of calorimeter with contents = m₃ gm and mass of lead shots = m₃ – m₂ gm.
• If the specific heats of the calorimeter, lead shots and water are S_c, S_l and S_w respectively, by using method of mixtures we have
  Heat lost by the solid = Heat gained by the calorimeter + water
  
• Knowing the specific heats of calorimeter and water we can calculate specific heat of solid (lead shots).

Question 8.
Convert 20° C into Kelvin scale. (or) Change 20°C into absolute scale. (AS1)
Answer:
T = t°C + 273 = 20 + 273 = 293
⇒ T = 293 K.

Question 9.
Your friend is asked to differentiate between evaporation and boiling. What questions could you ask to make him to know the differences between evaporation and boiling? (AS2)
(OR)
Veena found that the water kept in a pot is cool and Siva observed when water is heated the temperature remains constant for some time until water turns into vapour. What are the processes involved in these two aspects? Ask some questions to understand these aspects.
Answer:
The questions asked by me are :

• How do wet clothes get dried without heating?
• Are boiling and evaporation one and same or different?
• Is there any difference in kinetic energy if it boils?
• Is the temperature the main cause for boiling and evaporation?
• What are the factors which influence evaporation?
• Is boiling temperature for water always 100° C?

Question 10.
What happens to the water when wet clothes dry? (AS3)
Answer:

1. When wet clothes dry, the water present in the clothes is evaporated.
2. So that the process of evaporation causes the wet clothes dry.

Question 11.
Equal amounts of water are kept in a cap and in a dish. Which will evaporate faster? Why? (AS3)
(OR)
Srinu kept. equal amounts of water in a cap and in a dish in open air. What is his observation? Explain the experiment.
Answer:
Aim : To show the evaporation of equal amounts of water in cap and dish.
Apparatus : Cap, dish, water.

Procedure :

• Take equal amounts of water in cap and dish. Keep them in open air for two hours. Now weigh the water in the cap and the dish.
• We can observe that the weight of water in dish is less than that of water in cap.
• This shows that the water in dish has more evaporation than the water in cap.
• It is due to more surface area of dish.
• As the surface area increases rate of evaporation also increases.

Question 12.
Suggest an experiment to prove that rate of evaporation of a liquid depends on its surface area and vapour already present in surrounding air. (AS3)
Answer:
Aim: The rate of evaporation of liquid depends on its surface area and vapour already present in surrounding air.
Apparatus : Two dishes of different surface areas and water.

Procedure :

• Take two dishes of different surface area.
• Pour equal amounts of water in the both dishes.
• Keep aside for two to three hours.
• Observe them after some time.
  Dish with more surface area has less quantity of water than the dish having less surface area. ,
• This shows evaporation increases with increasing of surface area.
• Take two dishes of equal surface area containing water.
• This experiment should be conducted on more humid day and less humid day.
• We will find that evaporation is less on more humid day due to more vapour in the air.
• So evaporation decreases with vapour in the air.

Question 13.
Place a Pyrex funnel with its mouth-down in a sauce pan full of water, in such a way that the stem tube of the funnel is above the water or pointing upward into air. Rest the edge of the bottom portion of the funnel on a nail or on a coin so that water can get under it. Place the pan on a stove and heat it till it begins to boil. Where do the bubbles form first? Why? Can you explain how a natural geyser works using this experience? (AS4)
Answer:

• When Pyrex funnel with its mouth down in a sauce pan then the bubbles formed by the heat energy come from the top of the funnel.
• That is from stem tube.
• This is because of pressure inside mouth of funnel increases rapidly due to increasing of heat energy.
• Pressure inside the funnel rs more than outside the funnel and very high at stem.
• Hence, bubbles come from stem of the funnel and escapes through stem tube with force, like a geyser.

Working of natural geyser by using this experience :

• Geysers are the fountains of hot water coming under the layers of the earth.
• It is a hole with narrow and deep from the bottom of the earth layers.
• It contains water.
• Water heats up due to high temperatures of the inner layers of the earth.
• As by the pressure of water at top layers of the hole, temperature rises, water boils.
• This hot water comes with narrow vent with high pressure, like Lava from the Volcano.

Question 14.
Collect the information about working of natural geyser and prepare a report. (AS4)
Answer:
Natural Geysers :

• Geysers are the fountains of hot water coming under the layers of the earth.
• It is a hole with narrow and deep from the bottom of the earth layers.
  
• It contains water.
• Water heats up due to high temperatures of the inner layers of the earth.
• As by the pressure of water at top layers of the hole, temperature rises, water boils.
• This hot water comes with narrow vent with high pressure, like Lava from the Volcano.
• This looks like a water fountain at the surface of the earth.
  

Question 15.
Assume that heat is being supplied continuously to 2 kg of ice at – 5°C. You know that ice melts at 0°C and boils at 100°C. Continue the heating till it starts boiling. Note the temperature for every minute. Draw a graph between temperature and time using the values you get. What do you understand from the graph ? Write the conclusions. (AS5)
Answer:
Graph between time and temperature from ice melting at 5° C to boils at 100° C.

Understanding from the graph :

• \(\overline{\mathrm{AB}}\) = Ice warms up from – 5°C to 0°C
• \(\overline{\mathrm{BC}}\) = Ice melts at 0°C for a certain time period. So \(\overline{\mathrm{BC}}\) indicates no rising in temperature.
• \(\overline{\mathrm{CD}}\) = Water warms up from 0°C to 100° C, \(\overline{\mathrm{CD}}\) indicates rising in temperature.
• \(\overline{\mathrm{DE}}\) = Water boils at 100° C for a certain time period. So \(\overline{\mathrm{DE}}\) indicates no rising in temperature.

Conclusion :

• The temperature remains same at 0° C until all the ice converted into water. So, 0° C is the melting point of water.
• The temperature remains constant at 100° C until all the water converted into water vapour. So, 100° C is the boiling point of the water.

Question 16.
How do you appreciate the role of the higher specific heat of water in stabilising atmospheric temperature during winter and summer seasons? (AS6)
Answer:

• Due to higher specific heat of water oceans absorb the solar energy for maintaining a relatively constant temperature.
• Oceans absorb large amounts of heat at the equator.
• The oceans moderate the surrounding temperature near the equator.
• Ocean water transports the heat away from the equator to areas closer to the north and south pole.
• This transported heat helps moderate the climate in parts of the Earth that are far from the equator.
• So higher specific heat of water is stabilising atmospheric temperature.
• So we have to extremely appreciate the role of higher specific heat of water to stabilise the atmospheric temperature.

Question 17.
Suppose that 1 / of water is heated for a certain time to rise and its temperature by 2°C. If 2 l of water is heated for the same time, by how much will its temperature. (AS7)
Answer:
Mass of 1 litre of water (m₁) = 1 kg ; ∆T₁ = 2°C
Mass of 2 litres of water (m₂) = 2 kg ; ∆ T₂ = ?
Time duration is same. So same heat is absorbed by water in both the cases
⇒ Q₁ = Q₂
m₁S(∆T₁) = m₂S (∆T₂)

So the rise in temperature for 2 kg of water = 1°C.

Question 18.
What role does specific heat play in keeping a watermelon cool for a long time after removing it from a fridge on a hot day? (AS7)
Answer:

• Generally, watermelon contains large percentage of water.
• Water has high specific heat value than other substances.
• High specific heat substances oppose the increase of temperature. Hence they continuous of the coolingness.
• So watermelon retains coolness after removing from fridge on a hot day due to the high specific cheat of water.

Question 19.
If you are chilly outside the shower stall, why do you feel warm after the bath if you stay in bathroom? (AS7)
Answer:

• In the bathroom, the number of vapour molecules per unit volume is greater than the number of vapour molecules per unit volume outside the room.
• When we try to dry ourselves with a towel, the vapour molecules surrounding you condense on your skin.
• Condensation is a warming process.
• Because of the condensation, you feel warm outside the shower stall when it is chilly.

Question 20.
Three objects A at 30°C, B at 303K and C at 420 K are in thermal contact. Then answer the follwing questions.
(i) Which are in “Thermal equibrium” among A, B and C?
(ii) From which object to another heat transferred? (2 Marks)
Answer:
i) 303K – 273K + 30K = 0°C + 30°C = 30°C.
∴ A and B objects are in ‘Thermal equibrium”.
ii) From object ‘C’ to objects ‘A’ and ‘B’ heat transferred.

Fill in the Blanks

1. The SI unit of specific heat is …………………. .
2. …………………. flows from a body at higher temperature to a body at lower temperature.
3. …………………. is a cooling process.
4. An object A at 10° C and another object B at 10 K are kept in contact, then heat will flow from …………………. to …………………. .
5. The latent heat of fusion of ice is …………………. .
6. Temperature of a body is directly proportional to …………………. .
7. According to the principle of method of mixtures, the net heat lost by the hot bodies is equal to …………………. by the cold bodies.
8. The sultryness in summer days is due to
9. …………………. is used as a coolant.
10. Ice floats on water because …………………. .
Answer:

1. J/kg – K
2. Heat
3. Evaporation
4. A, B
5. 80 cal/gm
6. Average kinetic energy of the molecules of the body.
7. net heat gained
8. high humidity
9. Water
10. the density of ice is less than that of water

Multiple Choice Questions

1. Which of the following is a warming process?
A) evaporation
B) condensation
C) boiling
D) all the above
Answer:
B) condensation

2. Melting is a process in which solid phase changes to ………………. .
A) liquid phase
B) liquid phase at constant temperature
C) gaseous phase
D) any phase
Answer:
B) liquid phase at constant temperature

3. Three bodies A, B and C are in thermal equilibrium. The temperature of B is 45° C. Then the temperature of C is ……………… .
A) 45° C
B) 50° C
C) 40° C
D) any temperature
Answer:
A) 45° C

4. The temperature of a steel rod is 330 K. Its temperature in ° C is ……………… .
A) 55° C
B) 57° C
C) 59° C
D) 53° C
Answer:
B) 57° C

5. Specific heat S =

Answer: C

6. Boiling point of water at normal atmospheric pressure is ……………… .
A) 0° C
B) 100° C
C) 110° C
D) -5° C
Answer:
B) 100° C

7. When ice melts, its temperature ……………… .
A) remains constant
B) increases
C) decreases
D) cannot say
Answer:
A) remains constant

10th Class Physics 1st Lesson Heat InText Questions and Answers

10th Class Physics Textbook Page No. 1

Question 1.
Take a piece of wood and a piece of metal and keep them in a fridge or ice box. After 15 minutes, take them out and ask your friend to touch them. Which is colder? Why?
Answer:
1) The metal piece is colder than the wooden piece.
2) Because more heat energy flows out of our body so metal piece gives coldness to our body, than wooden piece.

Question 2.
What could be the reason for difference in coldness of metal and wood?
Answer:

• Due to more heat energy loss by our body when touches the metal piece compared to the wooden piece.
• In other way we say degree of coldness of the metal piece is greater than that of. the wooden piece.

Question 3.
Does it have any relation to the transfer of heat energy from our body to the object?
Answer:

• Yes, the principle of calorimetry, means heat loss by hot body is equal to heat gained by cold body.
• This means that when heat energy flows out of our body we feel the coldness and when heat energy enters our body we feel hotness.

10th Class Physics Textbook Page No. 2

Question 4.
Why does transfer of heat energy take place between objects?
Answer:

• Due to the temperature difference between the two bodies which are in thermal contact.
• Now heat energy transfers from hot body to cold body until they attain same temperature.

Question 5.
Does transfer of heat take place in all situations?
Answer:
No, when the bodies are in thermal equilibrium there is no transfer of heat energy.

Question 6.
What are the conditions for transfer of heat energy?
Answer:

• Two bodies should have difference in temperature.
• They (two bodies) are in thermal contact with each other.
• When the bodies have equal temperature there is no transfer of heat energy.

Question 7.
What is temperature?
(OR)
Define temperature.
Answer:
Temperature : The measure of hotness or coldness of a body is called temperature.

Question 8.
How can you differentiate temperature from heat?
Answer:

• Heat is a thermal energy that flows from hot body to cold body. Temperature is measure of the hotness or coldness of a body.
• Temperature decides direction of heat (energy) flow, whereas heat is energy itself that flows.

10th Class Physics Textbook Page No. 2 & 3

Question 9.
Place a laboratory thermometer in a glass tumbler containing hot water. Observe the change in mercury level. Wffet change did you notice in mercury level? Did mercury level increase or decrease?
Answer:
The mercury level rises up that means temperature of the mercury level increases.

10th Class Physics Textbook Page No. 3

Question 10.
Place a laboratory thermometer in a glass tumbler containing cold water. Observe the change in mercury level. Did mercury level decrease or increase?
Answer:
The mercury level falls down that shows temperature of the mercury level decreases.

Question 11.
If two different systems A and B in thermal contact, are in thermal equilibrium individually with another system C (thermal contact with A and B), will the systems A and B be in thermal equilibrium with each other?
Answer:
Yes, A and B will be in thermal equilibrium with each other that means A and B will have equal temperatures.

Question 12.
How would you convert degree Celsius to Kelvin?
Answer:
Temperature in Kelvin = 273 + Temperature in degree Celsius. [K = t°C + 273]

10th Class Physics Textbook Page No. 4

Question 13.
Take two bowls one with hot water and second with cold water. Gently sprinkle food colour on the surface of the water in both bowls. How do food grains move? Why do they move randomly?
Answer:
We will notice that the grains of food colour move randomly (jiggle). This happens because of the molecules of water on both bowls are in random motion.

Question 14.
Why do the grains in hot water move more rapidly than the grains in cold water?
Answer:

• Temperature kinetic energy. So molecules in hot water have more KE than molecules in cold water.
• As water molecules in hot water move rapidly, grains in hot water move more rapidly than the grains in cold water.

10th Class Physics Textbook Page No. 4 & 5

Question 15.
a) Take a cylindrical jar and pour hot water and then coconut oil in the vessel (do not mix them). Keep thermometers in hot water and coconut oil as shown in figure. The reading of thermometer in hot water decreases, at the same time reading of the thermometer, kept in oil increases. Why does this happen?
Answer:

• Heat transfers from hot water to oil.
• So, water loses heat and shows downfall in temperature.
• Oil takes the heat and shows increasing in the temperature.

b) Can you say that water loses energy’?
Answer:

• Yes. Due to the temperature difference between the water and oil, water loses energy and oil gains energy.
• Thus some heat energy flows from water to oil.
• This means, the kinetic energy of the molecules of water decreases while the kinetic energy of molecules of oil increases.

c) Can you differentiate between heat and temperature based on the heat transmit activity?
Answer:
Heat is the energy that flows from a hotter body to a colder body. Temperature denotes which body is hotter and which is colder. So, temperature determines direction of heat (energy) flow, whereas heat is the energy that flows.

10th Class Physics Textbook Page No. 5 & 6

Question 16.
Place two test tubes containing 50 gm of water, 50 gm of oil in boiling water for same time.
a) In which material does the temperature rise quickly? Are the amounts of heat given to the water and oil same? How can you assume this?
Answer:

• Rise in temperature of oil is faster than the water.
• Yes, same amount of heat energy given to both the oil and water through boiling water.

b) Why does this happen in specific heat?
Answer:
This happens because rise in temperature depends on the nature of substance.

10th Class Physics Textbook Page No. 7

Question 17.
How much heat energy is required to rise the temperature of unit mass of substance (material) by 1°C?
Answer:
Energy equal to its specific heat.

Question 18.
Why is the specific heat different for different substances?
(OR)
Explain why specific heat values are different for different materials.
Answer:

• We know that the temperature of the body is directly proportional to the average kinetic energy of particle of the body.
• The molecules of the system have different forms of energies such as linear, rotational kinetic energy, vibrational energy and potential energy.
• When we supply heat energy, it will be shared in different forms and increase the energy in the system.
• This sharing will vary from material to material.
• If the maximum share of heat energy is spent to rise linear kinetic energy, then the system gets increasing in temperature.
• Due to differences in sharing different materials have different specific heats.

10th Class Physics Textbook Page No. 8

Question 19.
Take 200 ml of water in two beakers and heat them to same temperature and pour the water of two beakers into a larger beaker.
What do you observe? What could be the reason for the fact you observed?
Answer:

• The temperature of mixture remains the same.
• The reason is that the masses rise in temperature and the materials are same.

Question 20.
Heat the water in one beaker to 90°C and the other to 60°C. Mix the water from these beakers in large beaker. What will be the temperature of the mixture? What did you notice? Can you give reason for the change in temperature?
Answer:

• The temperature of mixture is 75°C.
• The reason is for a given material the temperature of mixture,
  
• Hot water gives heat to the cold water until thermal equilibrium takes place.
• So, the thermal equilibrium attains at 75°C.

Question 21.
ake 100 ml of water at 90°C and 200 ml of water at 60°C and mix the two. What is the temperature of the mixture? What difference do you notice in change of temperature?
Answer:

• The temperature of mixture is 70°C.
• The reason is here m₁ = 100 gm ; m₂ = 200 gm
  
• Final temperature of the mixture is less than the above case.
• If the quantity increases, the quantity of heat to transfer is also rises to attain thermal equilibrium.
  Here hotter body quantity is less and colder body quantity is high. So, the temperature at thermal equilibrium decreases and stands at 70° C.

10th Class Physics Textbook Page No. 10

Question 22.
When floor of room is washed with water, the water on the floor disappears within minutes. Why does water on the floor disappear after some time?
Answer:
Due to evaporation water disappears from the floor.

Question 23.
Pour a few drops of spirit on your palm. Why does your skin become colder? (1 Mark)
Answer:
Spirit absorbs heat energy from our palm and evaporates. So our palm becomes colder.

10th Class Physics Textbook Page No. 10 & 11

Question 24.
Take a few drops of spirit in two petri dishes separately. Keep one of the dishes under a ceiling fan and switch on the fan. Keep another dish with its lid closed. What do you notice? What could be the reason for this change?
Answer:
1) The spirit in the dish which is kept under the ceiling fan disappears.
2) Whereas we will find some spirit left in the dish that is kept in the lidded dish.
3) The molecules which are escaping from the surface is high and they can’t reach back to liquid due to wind blow. So, evaporation is high under fan.
4) At the same time evaporation is less in the dish which is closed by lid.

10th Class Physics Textbook Page No. 12

Question 25.
Does the reverse process of evaporation take place? When and how does it take place?
Answer:
1) Yes, the reverse process of evaporation takes place.
2) When the vapour molecules lose their kinetic energy which leads to lower the temperature, they convert into droplets.
3) This process is called condensation.

10th Class Physics Textbook Page No. 13

Question 26.
In early morning, during winter, you might have noticed that water droplets form on window panes, flowers, grass, etc. How are these water droplets formed?
(OR)
Why do water drops (dew) form on flowers and grass during morning hours of winter season?
Answer:

• During winter season, in the night times, atmospheric temperature goes down.
• The surfaces of window panes, flowers, grass, etc. become colder.
• The water vapour molecules touch the surfaces, gets cooled and lost its energy.
• Then water vapour condenses on the surface and water drops formed.
• The water droplets condensed on such surfaces are known as dew.

10th Class Physics Textbook Page No. 14

Question 27.
Are the process of evaporation and boiling the same? Explain.
Answer:

• No, they are different.
• Evaporation takes place at any temperature.
• But boiling occurs at particular temperature called the boiling point.

10th Class Physics Textbook Page No. 16

Question 28.
You might have observed coconut oil and ghee getting converted from liquid state to solid state during winter season. What could be the reason for this change? What happens to water kept in a refrigerator? How does it get converted from liquid phase to solid phase?
Answer:
1) If temperature of a substance decreases kinetic energy also decreases.
2) Kinetic energy decreases from water to ice. That means solid state to liquid state.
3) In winter season coconut oil in the form of liquid get down its temperature, hence its kinetic energy also decreases. So, it-freezes.
4) Water, which is kept in refrigerator loses the kinetic energy along with decreasing temperature and freezes.
5) In this way water converted liquid phase to solid phase.

Question 29.
Are the volumes of water and ice formed with same amount of water equal? Why?
Answer:
1) No, the volume of ice is greater than volume of water.
2) Water expands on freezing.
3) That means density of ice is less than density of water.

10th Class Physics 1st Lesson Heat Activities

Activity – 1

1. Explain the term temperature with example.
(OR)
What is the name given to degree of hotness or coldness? Explain the quantity with an example.
Answer:
Procedure: Take a piece of wood and a piece of metal and keep them in fridge or ice box.
Observation : When we touch both of them we feel that metal piece is colder than the wooden piece.

Explanation :

• This is due to more energy flow out of our body when we touch the metal piece as compared with wooden piece.
• The degree of coldness of metal is greater than that of the wooden piece.
• The degree of hotness or coldness is called temperature.
• From this example, we say metal piece is at a lower temperature compared to wooden piece.

Activity – 2

2. What is the measure of thermal equilibrium? How do you prove?
(OR)
How do you prove temperature is the measure of thermal equilibrium?
(OR)
Explain thermal equilibrium with an activity.
Answer:
Procedure :
Take two glass tumblers and fill one of them with hot water and another with cold water.
Explanation & Observation :
1) When we place a thermometer inside the hot water the mercury level of thermometer rises from initial position due to heat transferred from hotter body (hot water) to colder body (mercury in thermometer).
2) When we place the thermometer inside the cold water the mercury level comes down from its initial position due to transfer of heat from mercury (hotter body) to water (colder body).

Conclusion :

• Heat is a form of energy that flows from a body at higher temperature to a body at lower temperature until the temperature remains same for two bodies that is called thermal equilibrium.
• In the above case, the steadiness of mercury column shows that thermal equilibrium is achieved. That reading of mercury column gives temperature.
• Thus temperature is a measure of thermal equilibrium.

Activity – 3

3. Establish the relationship between temperature and average kinetic energy.
(OR)
Suggest an activity to prove that the average kinetic energy of the molecules is directly proportional to the absolute temperature of the substances.
(OR)
How do you prove that temperature of a body is an indicator of average kinetic energy?
Answer:
Procedure :

• Take two bowls one with hot water and second with cold water.
• Gently sprinkle food colour on the surface of the water in both bowls.

Observation :
We will observe the jiggling of grains of food colour in hot water is more when compared to jiggling in cold water.

Explanation :

• We know kinetic energy depends on speed motion of particles.
• So the kinetic energy of hotter body is greater than that of colder body.
• Thus the temperature of a body is an indicator of average kinetic energy of molecules of that body.

Conclusion :
Therefore average kinetic energy of molecules is directly proportional to absolute temperature.

Activity – 4

4. Write an activity which tells how heat transmits.
(OR)
In which direction does heat tend to flow? Prove it with an activity.
Answer:

Procedure :

• Take water in a container and heat it to 60° C.
• Take a cylindrical transparent glass jar and fill half of it with the hot water.
• Pour coconut oil over the surface of water.
• Put a lid with two holes on the top of the glass jar.
• Insert two thermometers through the lid in such a way that one inside coconut oil and other in water.

Observation & Explanation :

• Now we can observe that the reading of thermometer kept in water decreases while the reading of thermometer kept in oil increases.
• So temperature of water decreases whereas temperature of oil increases.

Conclusion :

• Heat transmits from hotter body to colder body.
• So temperature determines direction of heat flow.

Activity – 5 Specific Heat

5. Write an activity which gives the relation between rise in temperature and nature of material.
(OR)
“The rate of rise in temperature depends on the nature of substance.” Prove it with an activity.
(OR)
Draw a diagram and label the parts to prove that the rate of increase in temperature depends on the nature of substance.
(OR)
We can observe severe burns with hot oil when compared with hot water.
Which factor will decide this aspect? Explain this process with an example.
Answer:
Procedure :

• Take a large jar with water and heat it up to 80°C.
• Take two identical boiling test tubes with single-holed corks.
• Fill them, one of the boiling tubes with 50 gm of water and other with 50 gm of oil.
• Insert two thermometers in each of tubes and clamp them to retort stand and place them in a jar of hot water.

Observation :

• Observe the readings of thermometers every three minutes.
• We can observe that the rise in temperature of oil is higher than that of water.

Explanation :

• Since both the boiling tubes kept in hot water for the same interval of time, the heat supplied to oil and water is same but rise in temperature of oil is more.
• So we conclude that rise in temperature depends on the nature of substance (specific heat).

Activity – 6

6. Derive Q = mSAT.
(OR)
Establish relationship between heat energy, mass of the substance and rise in temperature.
(OR)
Derive an expression for heat energy.
(OR)
Derive an expression for factors affecting amount of heat energy absorbed.
Answer:
Procedure :

• Take two beakers of equal volume and take 250 grams of water in one beaker and 1 kg of water in another beaker.
• Note their initial temperatures.
• Now heat the two beakers up to 60° C.
• Note down the heating times.

Observation:

• We observe that-the water in large beaker takes more time.
• That means we need to supply more heat enepgy to water in larger beaker (greater quantity of water).

Conclusion :
From this we conclude that for some change in temperature the amount of heat (Q) absorbed by a substance is directly proportional to its mass (m).
Q ∝ m (when ∆T is constant) ………….. (1)

Procedure :
Now take 1 litre of water in a beaker and heat it and note the temperature changes (∆T) for every two minutes and observe the rise internals.

Conclusion:
We will notice that for the same mass (m) of water the change in temperature is proportional to amount of heat (Q) absorbed by it.
Q ∝ ∆T (when m is constant) ………….. (2)
From (1) and (2) Q m∆T (or) Q = mS∆T,
where ‘S’ is called specific heat of substance.

Activity – 7

7. a) How are you able to find the final temperature of the mixture of sample?
(OR)
What is the “Principle of method of mixtures”? Verify it with an activity.
Answer:
Situation – 1 :

• Take two beakers of the same size and pour 200 ml of water in each of them.
• Now heat the water in both beakers to same temperature.
• Now pour water from these beakers into a larger beaker and measure the temperature of the mixture.

Observation :
We can observe that there is no change in temperature.

Situation – 2 :

• Now heat the water in first beaker to 90° C and the other to 60° C.
• Mix the water from these beakers in a large beaker.

Observation :
We can find that the temperature of mixture is 75° C.

Situation – 3 :
Now take 100 ml of water at 90° C and 200 ml of water at 60° C and mix the two. Observation :
We can find that the temperature of mixture is 75° C.

7. b) Derive, a formula for final temperature of mixture of samples.
(OR)
Maveen added hotter water of mass m₁ kept at temperature T₁ to cold water of mass m₂ kept at temperature T₂. Find the expression to find temperature of mixture of samples.
Answer:
Procedure:
1) Let the initial temperatures of the hotter and colder samples of masses m₁ and m₂ be T₁ and T₂.
2) Let T be the final temperature of mixture.

Observation :
The temperature of the mixture is lower than hotter sample and higher than colder sample. Explanation :
So hot sample has lost heat, and the cold sample has gained heat.
The heat lost by the hot sample Q₁ = m₁S (T₁ – T)
The heat gained by the cold sample Q₂ = m₂S (T – T₂)
We know that heat lost = heat gained
Q₁ = Q₂
m₁ S(T₁ – T) = m₂ S(T – T₂)
\(\mathrm{T}=\frac{\mathrm{m}_{1} \mathrm{~T}_{1}+\mathrm{m}_{2} \mathrm{~T}_{2}}{\mathrm{~m}_{1}+\mathrm{m}_{2}}\)

Activity -8

8. Explain the process of evaporation phenomenon with an example.
(OR)
Srinu observed that spirit taken in a petri dish disappears after some time. Explain the process involved in it with an example.
Answer:
Procedure :

• Take a few drops of spirit in two petri dishes separately.
• Keep one of the dishes under a ceiling fan and keep another dish with its lid closed.
• Observe the quantity of spirit in both dishes after 5 minutes.

Observation :
We will notice that spirit in the dish kept under the ceiling fan disappears whereas we will find some spirit left in the dish that is kept in the lidded dish.

Explanation :

• The reason is that the molecules of spirit in dish continuously move with random speeds and collide with other molecules.
• During the collision they transfer energy to other molecules.
• Due to this collision the molecules at the surface acquire energy and fly off from the surface.
• Some molecules come back to liquid.
• If the number of escaping molecules is greater than returned number, then the number of molecules in the liquid decreases.

Conclusion :
When a liquid is exposed to air, the molecules at the surface keep on escaping from the surface till the entire liquid disappears into air. This process is called evaporation.

Activity – 9

9. Explain the process of condensation with example.
(OR)
Explain the process of condensation with an activity.
(OR)
Karan told his friend that he observed that there are some water droplets outside a cold soft drink bottle. Explain the phenomenon involved in the formation of these droplets.
Answer:
Procedure :
Place a glass tumbler on the table. Pour cold water up to half of its height.

Observation :
There are droplets formed outside of the glass.

Explanation :

• The reason is that the surrounding air contains water molecules in the form of water vapour. When the water molecules strike the surface of the glass tumbler which is cool, they lose their kinetic energy.
• This energy lowers the temperature of vapour and it turns into droplets.
• The energy lost by water molecules in air is gained by the molecules of the glass tumbler.
• Hence the average kinetic energy of glass molecules increases. In turn the energy is transferred to water molecules in die glass.

Conclusion :

• So the average kinetic energy and temperature of water in glass increases. This is called condensation.
• Condensation is the phase change from gas to liquid.

Activity – 10

10. Explain the process of boiling with an example.
(OR)
Why do we observe bubbles on the surface of water which has been heated ? What is the phenomenon involved in it? Explain.
Answer:
Procedure :
Take a beaker of water, keep it on the burner and note the readings of thermometer for every two minutes.

Observation :

• We will notice that the temperature of the water rises continuously till it reaches 100° C.
• Once it reaches 100° C the temperature remains same and a lot of bubbling on the surface takes place. This is called boiling of water.

Explanation :

• It happens due to when water is heated the solubility of gases it contains reduces.
• As a result, bubbles of gas are formed in the liquid.
• Evaporation of water molecules from the surrounding liquid occurs into these bubbles and they become filled with saturated vapour.
• At a certain temperature, the pressure of the saturated vapour inside the bubbles becomes equal to the pressure exerted on the bubbles from the outside.

Conclusion :

• As a result, these bubbles rise rapidly to the surface and collapse at the surface releasing vapour present in bubbles into air at the surface. This process is called “boiling”.
• This temperature is called ‘boiling temperature”.

Activity – 11

11. Explain the process of melting and latent heat of fusion.
(OR)
When ice is heated to 0°C it starts to turn into water. But temperature remains ‘ constant for some time. What is the process involved in this? Explain.
Answer:
Procedure :

• Take small ice cubes in a beaker. Insert the thermometer in the beaker.
• Now start heating the beaker and note down readings of thermometer every one minute till the ice completely melts and gets converted into water.
• Before heating the temperature of ice is 0°C or less than 0°C.

Observation :

• We will observe that the temperature of ice at the beginning is equal to or below 0°C.
• If the temperature of ice is below 0°C, it goes on changing till it reaches 0°C.
• When ice starts melting, we will observe no change in temperature though you are supplying heat continuously.

Explanation:

• Given heat energy uses to break the bonds (H₂O) in ice and melts.
• So, temperature is constant while melting.

Conclusion:

• This process is called melting. In this process, heat converts solid phase to liquid phase.
• The temperature of the substance does not change until all the ice melts and converts into water.
• The heat given to melting is called latent heat of fusion.
• The heat required to convert 1 gm of solid completely into liquid at constant temperature is called “latent heat of fusion”.

Activity – 12

12. Why does a glass bottle tilled with water break when it is placed in deep freezer for some time?
(OR)
Prove that density of ice is less than that of water.
(OR)
How do you prove that volume of ice is more than that of water?
Answer:
Procedure :

• Take a small glass bottle with a tight lid and fill it with water, without any gap and fix the lid tightly.
• Put the bottle into the deep freezer of a refrigerator for a few hours.

Observation :
When we take it out from the deep freezer, we can observe that the glass bottle breaks.

Explanation :

• These cracks on the bottle due to expansion of the substance in the bottle.
• This means water expands on freezing.

Conclusion :

• Water expands on freezing.
• Ice has less density than water.