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These AP 9th Class Social Studies Important Questions 19th Lesson Expansion of Democracy will help students prepare well for the exams.

AP State Syllabus 9th Class Social 19th Lesson Important Questions and Answers Expansion of Democracy

9th Class Social 19th Lesson Expansion of Democracy 1 Mark Important Questions and Answers

Question 1.
The map below shows the democratic countries that existed between 1900 and 1950. (SA-II : 2018-19)

Answer:
Canada, Great Britain, U.S.A., Alaska, Peru, Chile, etc

Question 2.
Name the country which is marked by “A”. (SA-II : 2016-17)

Answer:
Russia.

9th Class Social 19th Lesson Expansion of Democracy 2 Marks Important Questions and Answers

Question 1.
Do you think our country has a liberal democratic political system? Give your reasons? (SA-II : 2016-17)
Answer:
Yes, our country has a liberal democratic political system by following methods.

1. Free and fair regular elections.
2. Written constitution.
3. Equality before law.
4. Universal Adult Franchise etc.

9th Class Social 19th Lesson Expansion of Democracy Important Questions and Answers

Question 1.
Compare the struggles for democracy in Libya and Burma on the following aspects
A) Leadership
B) Nature of struggle
C) Process of transition.
Answer:

Libya	Burma
A. Leadership	A. Leadership
1. Monarchy was established in 1951 under the leadership of king Idris.	1. Democracy was established. Three elec­tions were held in 1951, 56 and 1960.
2. Monarchy was overthrown by “Revolutionary Command Council” under the leadership of Muammar Gaddafi in 1969.	2. In 1962, the elected government was overthrown by a coup and army. General “Ne Win” took charge of the country.

B. Nature of Struggle	B. Nature of Struggle
1. People took the help of mobiles and internet.	1. People took the lead and thousands were brutally killed.
2. They protested against the military regime.	2. Suu Kyi was a central figure in the for establishing democracy in Burma.
3. Soon there broke out a civil war.	3. In 1990 Suu Kyi’s ‘NLD’ won the majority but was not allowed to form government and was kept under house arrest.
4. Gaddafi’s army crushed the protests and thousands were killed.

C. Process of transfer	C. Process of transfer
1. “UNO” intervened and declared Libya as “No fly zone”	1. Economic sanctions were imposed on Burma.
2. France, US, Britain etc., jointly used their force to bombard Libyan government.	2. There were a world wide pressure on the military government to extent civil liberty.
3. Libyans succeeded in overthrowing Gaddafi regime.	3. Elections were held in 2010 but due to the allegations of malpractices, the military junta was dissolved.
4. A new government was sworn in on14th Nov 2012.	4. Thein Sein became the president of Burma.
5. The story is still incomplete.	5. The struggle is still incomplete.

Question 2.
Read the following information and answer the questions given below.
Events and year of occurrence

1) Which of the above two countries first became independent? And when did it happen?
Answer:
Burma was the first country to get independence. And she got it in 1948.

2) Who was the dictator that ruled over Libya?
Answer:
“Gaddafi” ruled over Libya.

3) Who was Aung San?
Answer:
Aung San was the leader of Nationalist movement in Burma.

4) Which of the two countries became democratic first?
Answer:
Burma in 2010.

5) Where are the two countries located?
Answer:
Libya is in Africa and Burma is in Asia.

Question 3.
What are “economic sanctions” ? How do they work on any country’s economy?
Answer:

• Economic sanctions are restrictions imposed on any country regarding imports and exports.
• Import of goods from that country will be banned.
• Export of goods to that country will be stopped.
• Due to that the country’s economy will generally be effected.

Question 4.
What are the steps taken by “the UNO” with regard to Libya or Burma?
Answer:

• The UNO intervened and supported rebels by declaring Libya to be a “No fly zone”.
• Later with the help of US, Britain and France it bombarded the government positions in Libya.
• As a result a new government was formed in on 14th Nov. 2012,
• “Economic Sanctions” were imposed to put pressure on rulers.
• An election was held under the observation of the UNO in 2010.

These AP 10th Class Physical Science Chapter Wise Important Questions 8th Lesson Structure of Atom will help students prepare well for the exams.

AP State Syllabus 10th Class Chemistry 8th Lesson Important Questions and Answers Structure of Atom

10th Class Chemistry 8th Lesson Structure of Atom 1 Mark Important Questions and Answers

Question 1.
Write the electronic configuration of chromium. (AP June 2016)
Answrr:
The electronic configuration of chromium is
1s²2s²2p⁶3s²3p⁶4s¹3d⁵ or [Ar] 4s¹3d⁵

Question 2.
Out of 3d and 4s, which has more (n + l) value? Explain. (AP June 2017)
Answer:
1) 3d ⇒ n + l ⇒ 3 + 2 ⇒ 5 (energy)
4s ⇒ n + l ⇒ 4 + 0 ⇒ 4 (energy)

2) Hence, ‘3d’ has more (n + l) value than ‘4s’.

Question 3.
Prepare a question on nl^x method. (AP SA-I:2018-19)
Answer:

• How is nl^x method useful.
• Explain the nl^x method with an example.

Question 4.
Which colours do you observe when an iron rod is gradually heated to higher tem-peratures? (TS June 2015)
Answer:
First iron turns into red (lower energy corresponding to higher wavelength) and as the temperature rises it glows and turns into orange, yellow, blue or even white respectively (higher energy and lower wavelength).

Question 5.
Which principle is not followed in writing the electronic configuration of 1s² 2s¹ 2p⁴? Give reasons. (TS June 2015)
Answer:
1) Principle :
Aufbau principle is not followed in writing the electronic configuration of 1s² 2s¹ 2p⁴.

2) Reasons :
i) According to Aufbau principle electron enters into orbital of lowest energy.
ii) Between 2s and 2p, 2s has least energy. So 2s must be filled before the electron has to enter 2p.

Question 6.
Write the symbol of the outermost shell of magnesium (Z = 12) atom. How many electrons are present in the outermost shell of magnesium? (TS June 2017)
Answer:
Symbol of the outermost shell of magnesium (3rd shell) = M
No. of electrons in outermost shell of Magnesium = 2.

Question 7.
The four quantum number values of the 21st electrons of scandium (Sc) are given in the following table. (TS March 2017)

Write the values of the four quantum numbers for the 20th electron of scandium (Sc) in the form of the table.
Answer:

Question 8.
If n = 3, mention the orbitals present in the shell and write maximum number of electrons in the shell. (TS March 2018)
(OR)
Write the maximum number of electrons and number of orbitals in the shell, when n = 3.
Answer:

1. When n = 3, number of subshells = 3 (3s₁ 3p₁ 3d)
2. Number of orbitals = 9 (3s(1) 3p(3) 3d(5))
3. Maximum number of electrons (3s² 3p⁶ 3d¹⁰) = 18

Question 9.
What is dispersion?
Answer:
The splitting of light into different colours is called dispersion.

Question 10.
What is an electromagnetic wave?
Answer:
When electric field and magnetic fields are perpendicular to each other and at right angles to the direction of propagation of wave is formed. Such a wave is called electromagnetic wave.

Question 11.
What is a Zeeman effect?
Answer:
The splitting of spectral lines in the presence of magnetic field is called Zeeman effect.

Question 12.
What is a spectrum?
Answer:
Group of wavelengths is called spectrum (or) A collection of dispersed light giving its wavelength composition is called a spectrum.

Question 13.
What is speed of electromagnetic wave?
Answer:
It is equal to speed of light, i.e. 3 x 10⁸ ms^-1

Question 14.
Which colour has highest wavelength and which colour has least wavelength on visible spectrum?
Answer:
The colour that has highest wavelength in visible spectrum is red and least wavelength is violet.

Question 15.
If n = 5, then what is the maximum value for l?
Answer:
The maximum value for l is 4.

Question 16.
If l = 4, what is the number erf values for m_l?
Answer:
m_l = 2l + 1 = 2(4) +1=9.

Question 17.
What are the values of m_s?
Answer:
½ or – ½

Question 18.
What is electronic configuration?
Answer:
Distribution of electrons in shells, sub-shells and orbital in an atom is known as electronic configuration.

Question 19.
What is Heisenberg’s principle of uncertainty?
Answer:
It is not possible to find the exact position and velocity of electron simultaneously.

Question 20.
Give ascending order of various atomic orbitals according to Moeller diagram.
Answer:
1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4d < 5d < 6p < 7s < 5f < 6d < 7p < 8s.

Question 21.
What is Hund’s Rule?
Answer:
Electron pairing in orbitals starts only when all available empty orbitals of the same energy are singly occupied.

Question 22.
What is Planck’s equation?
Answer:
Planck’s equation is E = hv.
E = Energy of the radiation
h = Planck’s constant = 6.625 × 10^-34 J
v = Frequency of radiation.

Question 23.
What is electromagnetic spectrum?
Answer:
Electromagnetic waves can have a wide variety of wavelengths. The entire range of wavelengths is known as the electromagnetic spectrum.

Question 24.
What is wavelength?
Answer:
The distance from one wave peak to the next is called wavelength (λ).

Question 25.
What is frequency?
Answer:
The number of wave peaks that pass by a given point per unit time is called frequency.

Question 26.
When are electromagnetic waves produced?
AnElectromagnetic waves are produced when an electric charge vibrates.

Question 27.
Which is the example for line spectrum?
Answer:
The atomic spectrum of hydrogen atom.

Question 28.
Which model explains fine spectrum of atom?
Answer:
Bohr – Sommerfeld model.

Question 29.
How are wavelength and velocity of light related?
Answer:
c = vλ
where
c = velocity of light,
v = frequency of light,
λ = wavelength of light.

Question 30.
Give the equation which gives electromagnetic energy (light) that can have only Certain discrete energy values.
Answer:
E = hv
E = Energy of light
h = Planck’s constant = 6.62 5 × 10^-27 erg sec or 6.625 × 10^-34 Joule-sec
v = Frequency of radiation
This equation is called Planck’s equation.

Question 31.
Which group elements are called Noble gases?
Answer:
VIII A group or 18th group elements are called inert gases (or) Noble gases.

Question 32.
Which elements are highly stable?
Answer:
Noble gases are highly stable.

Question 33.
Write the set of quantum numbers for the electrons in a 3p_z orbital.
Answer:

Question 34.
What is the difference between an orbit and orbital?
Answer:
An orbit is a well defined path of electron that revolves around the nucleus.

An orbital is the space around the nucleus, where the probability of finding electrons is maximum.

Question 35.
What are the factors which influence electromagnetic energy?
Answer:
Electromagnetic energy depends on two factors

1. wavelength
2. frequency.

Question 36.
What is a wave?
Answer:
The disturbance occurred in a medium is called wave.

Question 37.
When cupric chloride is kept in non-luminous flame then what is the colour of flame?
Answer:
Green colour.

Question 38.
If the colours gradually changes there are no sharp boundaries in between them, then what is the name given to that type of spectrum?
Answer:
Continuous spectrum of emission.

Question 39.
What is the information given by magnetic orbital quantum numbers?
Answer:
Orientation of orbitals in space.

Question 40.
How many orbitals are present in a sub-shell?
Answer:
The number of orbitals are present in a sub-shell is n² (where n is principal quantum number).

Question 41.
What happens when an object is suitably excited by heating?
Answer:
Light is emitted by the object.

Question 42.
What is meant by Aufbau?
Answer:
The German word Aufbau means building up.

Question 43.
Which elements are examples for Noble gases?
Answer:
Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and Radon (Rn) are examples for Noble gases.

Question 44.
Which element has duplet configuration?
Answer:
Helium (1s²)

Question 45.
Write the set of quantum number for the added electron of oxygen atom.
Answer:
Configuration of oxygen is 1s² 2s² 2p⁴.
The added electron is 4th in the 2p.
The set of quantum numbers (2, 1, -1, -½)

Question 46.
Can we apply c = vλ, to sound waves?
Answer:
Yes. It is a universal relationship and applies to all waves.

Question 47.
What is the value of Planck’s constant?
Answer:
The value of Planck’s constant is 6.626 × 10^-34 Js.

Question 48.
Why do different elements emit different flame colours when heated by the same non-luminous flame?
Answer:’
The light emitted by different kind of atoms is different because the excited states electrons will go are different.

Question 49.
How many values can ‘l’ have for n = 4?
Answer:
If n = 4, l can take values 0, 1, 2, 3. So there are four values.

Question 50.
Write the four quantum numbers for the differentiating electrons of lithium (Li) atom.
Answer:
The electronic configuration of lithium is 1s² 2s¹. So differentiating electron enters into 2s. The values of four quantum numbers are as given below.

Question 51.
Write four quantum numbers for 2p¹ electrons.
Answer:
The four quantum numbers for 2p are

Question 52.
Which rule is violated in the following electronic configuration?

Answer:
The rule violated is Hund’s rule.

Question 53.
How many maximum number of electrons that can be accommodated in N principle energy shell?
Answer:
For N shell n = 4.
The maximum number of electrons accommodated in a shell is 2n².
∴ A maximum of 32 electrons can be filled in N shell.

Question 54.
How many maximum number of electrons that can be accommodated in a ‘l’ sub-shell?
Answer:
l sub-shell has 3 orbitals. Each orbital accommodates 2 electrons. So 6 electrons can be filled in l sub-shell.

Question 55.
How many maximum number of electrons can be accommodated in ‘d’ sub-shell?
Answer:
d sub-shell has 5 orbitals. So 10 electrons can be filled in d sub-shell.

Question 56.
How many sub-shells present in a ‘M’ principal energy shell?
Answer:
For M shell n = 3
The number of sub-shells in M shell is 3.

Question 57.
How many spin orientations are possible for an electron in s-orbital?
Answer:
The spin quantum number values for electrons are ½ or -½. So 2 spin orientations are possible.

Question 58.
Write valence electronic configuration of element which has the following set of quantum numbers.
Answer:

n = 3 indicates 3rd orbit and l = 1 indicates p orbital and there is one electron in p orbital. So the valence electron configuration is 3p¹.

Question 59.
How many unpaired electrons are present in chromium?
Answer:
The electronic configuration of chromium 1s² 2s² 2p⁶ 3s² 3p6 4s¹ 3d⁵.

The number of unpaired electrons = 6.

Question 60.
Find the four quantum number values of 3^rd and 4^th electrons of Beryllium.
The electronic configuration of Beryllium is 1s² 2s².

Question 61.
What is the n + l value of 4f orbital?
Answer:
For 4f orbital n = 4 and f orbital l = 3.
∴ n + l = 4 + 3 = 7

Question 62.
When you heat iron rod first it turns red. Why?
Answer:
Iron turns into red because red has higher wavelength. So it has lower energy which is emitted by iron.

Question 63.
What is the significance of Planck’s proposal?
Answer:
Electromagnetic energy can be gained or lost in discrete values and not in a continuous manner.

Question 64.
When do you see an emission line?
The energy emitted by an electron is seen in the form of an electromagnetic energy and when the wavelength is. in the visible region it is visible as an emission line.

Question 65.
How many elliptical orbits are there in 4^th orbit of Sommerfeld?
Answer:
The number of elliptical orbits in 4^th orbit of Sommerfeld is 3.

Question 66.
Why is spin quantum number introduced?
Answer:
When we observe spectrum of yellow light by using high resolution spectroscope it has very closely spaced doublet. Similar patterns are shown by Alkali and Alkaline earth metals. In order to account this spin quantum number is introduced.

Question 67.
Which of the following magnetic quantum number values is not possible for 3d orbital?
a) – 2
b) – 1
c) 0
d) 4
Answer:
For d orbital the possible m; values – 2, – 1, 0, 1, 2. So the value 4 is not possible.

Question 68.
If an element has 11 electrons in its M shell, then what is the name of element and its atomic number?
Answer:
The electronic configuration of element is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d³.
[M shell electrons = 2 + 6 + 3=11]

So the element is Titanium.

Question 69.
The wave length of a wave is 100 nm. Find its frequency.
Answer:

10th Class Chemistry 8th Lesson Structure of Atom 2 Marks Important Questions and Answers

Question 1.
Explain Hund’s Rule with an example. (TS March 2016) (AP SA-1:2018-19)
Answer:
Hund’s Rule :
According to this rule electron pairing in orbitals starts only when all available empty orbitals of the same energy are singly occupied.

(1) Ex :

1. The configuration of carbon atom (Z = 6) is 1s² 2s² 2p².
2. The first four electrons go into the 1s and 2s orbitals.
3. The next two electrons go into 2p_x and 2p_y orbitals.
   
4. But, they do not pair in 2p_x orbital.

(2) Ex :

1. In oxygen atom (₈O), distribution of electrons is given below.
2. 
3. Here, pairing of electrons in 2px orbital takes place after, 2p_x, 2p_y and 2p_z orbitals are filled with a single electron.

Question 2.
The electronic configuration of Sodium is 1s² 2s² 2p⁶ 3s¹. (AP March 2017)
What information that it gives?
Answer:

1. Its atomic number is 11
2. It is s-block element
3. It is in 3rd period ’
4. It is in 1st group
5. Its valency is 1
6. Number of valency electrons are 1
7. It can form uni positive ion
8. It can form ionic bond, 9. It is metal.

Question 3.
Explain the principle which describes the arrangement of electrons in degenerate orbitals.
Answer:
According to Hund’s rule the degenerate orbitals are occupied with one electron each before pairing of electron starts.
Ex : Electronic configuration of carbon is 1s² 2s² 2p²

the last two electrons will enter into separate 2p orbitals.

Question 4.
Name the principle, which says an orbital can hold only 2 electrons and explain. (AP March 2018)
Answer:

• Name of the principle : Pauli’s exclusion principle.
• No, two electrons in an orbital can have all four quantum numbers same.
• It says there is a chance to hold only 2 electrons, one rotates in clockwise direction (+½)other rotates in anticlock wise direction (-½).

Question 5.
For a better understanding about the electronic configuration in an atom, the teacher wrote shorthand notation nl^x on the blackboard.
Looking at this notation, what could be the probable questions that generate in the student’s mind? Write any two of them. (TS March 2015)
Answer:

1. What n, l, x indicates related to atoms?
2. How nl^x indicates the position of the electrons in the atom?

Question 6.
Write the ‘Octet Rule’. How does Mg (12) get stability while reacting with chlorine as per this rule? (TS June 2017)
Answer:
Octet Rule :
The atoms of elements tend to undergo chemical changes that help to leave their atoms with eight outer – shell electrons.

Magnesium atom looses 2 electrons and get 8 electrons in its outermost shell as Neon. So that it gets stability.

Question 7.
Write the electronic configuration of the atom of an element having atomic number 11. Write the names of the rules and the laws followed by you in writing this electronic configuration. (TS March 2017)
Answer:
1s²2s²2p⁶3s¹.
(OR)
Principles followed :

1. Aufbau principle.
2. Hund’s Rule.
3. Pauli Exclusion Principle

Question 8.
The electron enters into 4s orbital after filling 3p orbital but not into 3d. Explain the reason (TS March 2018)
Answer:
Based on (n+l) values energy value of 3d orbitals is 3 + 2 = 5, energy value of 4s orbitals is 4 + 0 = 4
The energy level of 4s orbital is less than the 3d orbital according to the Aufbau principle electron enters into lower energy orbital first.
Thats why electrons enters into 4s orbital after filling 3p, but not into 3d.

Question 9.
Write the electronic configuration of Na⁺ and Cl^–.
Answer:
Electronic Configuration of Na⁺ is 1s² 2s² 2p⁶ and Cl^– is 1s² 2s² 2p⁶ 3s² 3p⁶.

Question 10.
Observe the given table and answer the following questions. (TS March 2019)

Sl.No.	Electron Configuration
1.	1s2 2s2 2p6 3s2 3p3
2.	1s2 2s2 2p6 3s2 3p6 4s2
3.	1s2 2s2 2p6 3s2 3p6

1) Mention the divalent element name.
2) Name the element belongs to 3^rd period and VA Group.
Answer:

1. Name of the divalent element in the table is Calcium.
2. Name of the element which belongs to 3^rd period and VA Group is Phosphorous.

Question 11.
Your friend is unable to understand nl^x. What questions will you ask him to understand nl^x method? (AP SCERT: 2019-20)
Answer:

1. What is nl^x method?
2. Where does it use ?
3. What is meant by ‘n’, 7′ and ‘x’?
4. How can we use nl^x method in the writing of electronic configuration?

Question 12.
Why do valency electrons involve in bond formation, than electrons of inner shells? (AP SCERT: 2019-20)
Answer:

1. When two atoms come sufficiently close together the valence electrons of each atom experience the attractive force of the nucleus in the other atom.
2. The nucleus and the electrons in the inner shell remain unaffected when atoms come close together.
3. The electrons in outer most shell of an atom get affected.
4. Thus electrons in valence shell are responsible for the formation of bond between atoms.

Question 13.
Explain Pauli’s exclusion principle with an example. (AP SA-I:2019-20)
Answer:
Pauli’s exclusion principle :
No two electrons of the same atom can have all four quantum numbers the same. If n, l and m_l are same for two electrons, then m_s must be different.
Suppose take the example of Helium atom.
The four quantum numbers for two electrons in the Helium atom given below.

We can observe from the table that three of the quantum numbers are same but fourth quantum number is different. The electronic configuration of Helium atom is² ↑↓. So the maximum number of electrons filled in an orbital is 2.

Question 14.
Explain Aufbau principle. (AP SA-I:2019-20)
Answer:
Aufbau principle :

1. In the ground state the electronic configuration can be built up by placing electrons in the lowest available orbitals until the total number of electrons added is equal to atomic number.
2. Thus orbitals are filled in the order of increasing energy.
3. Electrons are assigned to orbitals in order of increasing value of n + l.
4. For sub-shells with the same value of n + l, electrons are assigned first to the subshell with lower n.

Question 15.
The electronic configuration of an atom is as follows 1s² 2s² 2p².
a) Which element’s atom is it?
b) Which orbital is the last electron in?
c) When excited what could be the number of lone / single electrons in this atom?
d) What is the value of principal quantum numbers of two electrons in the first box?
Answer:
Given electronic configuration of atom is 1s² 2s² 2p².
a) The element is carbon.
b) The valence electron enters 2p orbital.
c) In excited state the electron in 2s orbital enters 2p orbital. So it has 4 unpaired electrons.
d) The value of principal quantum number is 1.

Question 16.
Draw the table which gives the information about the quantum numbers and the number of the quantum states.
Answer:

Question 17.
Explain briefly about spin quantum number.
Answer:

• This gives spin of the electrons about their own axes. It is denoted by ms.
• This quantum number refers to the two possible orientations of the spin of an electron, one clockwise and the other anti-clockwise spin.
• These are represented by +½ -½ and .

Question 18.
Write electronic configurations of following elements,
a) Hydrogen
b) Helium
c) Lithium
d) Beryllium
e) Boron
Answer:

Question 19.
What does a line spectrum tell us about the structure of an atom?
Answer:
The electrons in ground state i.e. lowest, energy state absorb energy and move into excited state where they are unable to stay for long periods so lose the energy and come back to the ground state. The emitted radiation appears as line in line spectrum.

Question 20.
What are the spins of electrons in Helium atom?
Answer:
The quantum numbers for two electrons of Helium are given below as per Pauli’s exclusive principle.

Three of quantum numbers are same. So fourth must be different so the two electrons have anti-parallel spins.

Question 21.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹ is the electronic configuration of Cu (Z = 29). Which rule is violated while writing this configuration? What might be the reason for writing this configuration?
Answer:
The rule violated is Aufbau principle. The elements which have half filled or completely filled orbitals have greater stability. So copper can get stability by transferring one electron from 4s to 3d (their energies are close to each other).

So the electronic configuration of copper is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹, not 1s² 2s² 2p 3s² 3p⁶ 3d⁹ 4s².

Question 22.
Why are chromium and copper exceptions to electronic configuration?
Answer:
Elements which have half-filled or completely filled orbitals have greater stability. So in chromium and copper the electrons in 4s and 3d redistribute their energies to attain stability by acquiring half-filled and completely filled d orbitals.

Hence the actual electronic configurations of chromium and copper are as follows.

Question 23.
Distinguish between emission and absorption spectrum.
Answer:

Emission spectrum	Absorption spectrum
1) The spectrum produced by emitted radiation is called emission spectrum.	1) The spectrum produced by absorption of radiation is called absorption spectrum.
2) The emission spectrum contains bright lines on the dark back-ground.	2) The absorption spectrum contains dark lines on the bright back-ground.
3) The emission spectrum corresponds the radiation emitted when an excited electron comes back to the ground state.	3) The absorption spectrum corresponds the radiation absorbed in exciting an electron from lower to higher energy levels.

Question 24.
Draw a table which will give the relationship between l values and number of orbitals and name of sub-shell and maximum number of electrons.
Answer:

Question 25.
Distinguish between line and band spectrum.
Answer:

Line spectrum	Band spectrum
1) The spectrum has sharp distinct lines.	1) The spectrum has many closed, spaced lines.
2) The spectrum is characteristic of atoms and is also called atomic spectrum.	2) The spectrum is characteristic of molecules is also called molecular spectrum.
3) The spectrum is given by inert gases, metal vapours and atomised non-metals.	3) The spectrum is given by hot metals and molecular non-metals.

Question 26.
What is Dispersion of light? Explain a natural example of dispersion of light.
Answer:
Dispersion:
Splitting of white light into colours (VIBGYOR) is called Dispersion of light.

The natural example for dispersion of light is formation of Rainbow. It is caused by dispersion of sunlight by tiny water droplets present in atmosphere which act as small prisms.

Question 27.
Wien is an electromagnetic wave produced? Write about characteristics of electromagnetic wave.
Answer:
Electromagnetic wave is produced when an electric charge vibrates (moves back and fortn).

Characteristics of electromagnetic waves :

1. Efectric field and magnetic fields are perpendicular to each other and at right angles to direction of propagation of wave.
2. It travels with speed of light i.e., 3 × 10⁸ ms^-1.
3. Electromagnetic energy is characterized by wavelength (λ) and frequency (v). The relation is given by c = vλ.

Question 28.
The valence electron configuration of element is given as 4s¹. Then give the following information.
1) What is the name of that element?
2) What is the outermost orbit of element?
3) What is ‘l’ value of outermost sub-shell?
4) What is the atomic number of element?
Answer:

1. Potassium.
2. N
3. The outermost sub-shell is 4s its l value is ‘O’.
4. Its electronic configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹. So its atomic number is 19.

Question 29.
Write all the quantum numbers for valance electron of sodium.
Answer:

1. The electronic configuration of sodium is 1s² 2s² 2p⁶ 3s¹.
2. The valance orbital is 3s.
3. The quantum numbers for this orbital is
   

Question 30.
Give electronic configurations of following elements.
a) Sodium
b) Phosphorous
Answer:
Sodium – 1s² 2s² 2p⁶ 3s¹
Phosphorous – 1s² 2s² 2p⁶ 3s² 3p³

Question 31.
Why does nitrogen has more chemical stability when compared with oxygen?
Answer:
The electronic configurations of Nitrogen and Oxygen are as follows.

Nitrogen has half filled 2p³ configuration. So it has greater chemical stability when compared with Oxygen.

Question 32.
Ramu gave electronic configuration of potassium as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹ whereas Ravi expressed the configuration as 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹. Who gave the correct configuration? Why?
Answer:
Ravi gave the correct configuration because according to Aufbau principle after completion of 3p orbital electron may enter either 4s or 3d.
Their n + l values are given below.

Orbital	n + l Values
4s	4 + 0 = 4
3d	3 + 2 = 5

So 4s orbital has lower n + l value when compared with 3d orbital. So electron enters into 4s.

Question 33.
Given the valence electron configuration of an element is 4s¹. Then what are its quantum number values. Which element does it represent?
Answer:
Given valence electronic configuration is 4s¹. So n = 4 for ‘s’ sub shell l = 0 and if l is ‘O’ then m_l is also zero. m_s takes only two values that is +½ or -½ for convenience we can take m_s as +½.
∴ The quantum number values are like this

The element is potassium.

Question 34.
The atomic number of an element is 17, then calculate the total number of electrons present in its s and p orbitals.
Answer:
The element with atomic number 17 is chlorine.
Its electronic configuration is 1s² 2s² 2p⁶ 3s² 3p⁵.
So, the total number of electrons present in s orbitals = 2 + 2 + 2 = 6.
The total number of electrons present in p orbitals = 6 + 5 = 11.

Question 35.
Based on Aufbau’s principle, in which of the three 4d, 5p and 5s orbitals the electrons will be filled first? Why?
Answer:
According to Aufbau’s principle, the electron enters the orbital having lower n + l value. If both orbitals have same n + l values, electron enters the orbital with lower ‘n’ value.

Oprbital	n + l value
4d	4 + 3 = 7
5p	5 + 1 = 6
5s	5 + 0 = 5

So, 3s has least n + l value. Therefore the electron enters 5s orbital first.

Question 36.
Find the following.
1) Number of orbitals present in M orbit.
Answer:
Number of orbitals present in an orbit = n² For M orbit n = 3.
∴ So the number of orbitals = 3² = 9.

2) The maximum and minimum possible m_l values for 4f orbital.
Answer:
For f orbital ‘l’ value is 3. If l is 3, then m_l takes values from – 3 to + 3.
So the minimum value for m_l is – 3 and maximum value is + 3.

3) The possible values of l if n = 4.
Answer:
If n = 4, then l take values from 0 to 3 i.e., 0, 1, 2, 3.

4) The maximum number of electrons that can be filled in ‘N’ energy level.
Answer:
For N orbit n = 4. The maximum number of electrons present in a shell = n².
∴ The maximum number of electrons filled in N shell = 4² = 16.

Question 37.
How do the vibrating electric and magnetic fields around the charge become a wave that travel through space?
Answer:

• A vibrating electric charge creates a change in the electric field.
• The changing electric field creates a changing magnetic field.
• This process continues, with both the created fields being perpendicular to each other and at right angles to the direction of propagation of the wave.

Question 38.
What information do the quantum numbers provide?
Answer:
The quantum numbers describe the space around the nuclear where the electrons are found and also their energies.

Question 39.
An electron in an atom has the following set of four quantum numbers. Which orbital does it belong to?

n	l	ml	ms
3	0	0	+½

Answer:
The quantum numbers of an atom is given below.

n	l	ml	ms
3	0	0	+½

By using nl^x method n = 3, if l = 0 then the sub-shell is s.
So the electron belongs to 3s.

Question 40.
Look at the following table and answer the following questions.

a) What is the law that is voilated in the above table? State that law.
b) Write the correct table using that law.
Answer:
a) The law violated is Pauli’s Exclusive Principle. Pauli’s law states that no two electrons of the same atom can have all the four quantum numbers same.
b)

10th Class Chemistry 8th Lesson Structure of Atom 4 Marks Important Questions and Answers

Question 1.
Draw Moeller chart of filling order of atomic orbitals.
(OR)
Draw a diagram showing the increasing value of (n + l) of orbitals. (AP June 2017)
Answer:

The filling order of atomic orbitals (Moeller Chart)

Question 2.
Complete the following table based on quantum numbers related to atomic orbitals and electron of an atom. (AP SA-I-2018-19)

Answer:

Question 3.
Based on the information given in the table, answer the questions given below.

i) For the 4th main shell, how many values are there for m_l? What are they? (TS June 2016)
Answer:
1) There are 16 m( values in the 4th main shell.
2) They are

Orbital	ml values	Total
4s	0	1
4p	-1, 0, + 1	3
4d	-2, -1, 0, + 1, +2	5
4f	-3, -2, -1, 0, +1, +2, +3	7
Total		16

ii) For sub-shell with n = 3, l = 1, write the m, values.
Answer:
For sub – shell with n = 3, l = 1 the m, values are -1, 0, 1.

iii) Write the principal quantum number value for ‘N’ shell. How many sub-shells are there in the main shell?
Answer:

1. The principal quantum number value for ‘N’ shell is 4.
2. The number of sub-shells is 4. They are 4s, 4p, 4d, 4f.

iv) In the above table m_l and l values are given. Write a formula that gives the relationship between m_l and l based on those values.
Answer:
m_l (No. of values) = 2l + 1.

Question 4.
Observe the information provided in the table about quantum numbers. Then answer the questions given below it. (TS June 2017)

n	l	ml
1	0	0
2	0	0
	1	-1, 0, +1
3	0	0
	1	-1, 0, +1
	2	-2, -1, 0, +1, +2

i) Write the ‘l’ value and symbol of the spherical shaped sub-shell.
ii) How many values that ‘m_l‘ takes for 1 = 2? What are they?
iii) Write the symbols of the orbitals for l = 1 sub-shell.
iv) What is the shape of the sub-shell for l = 2? What is the maximum number of electrons that can occupy this sub-shell?
Answer:
i) Spherical shaped sub-shell “l” value is zero and symbol is ‘s’.
ii) Number of m; values for 1 = 2 is 5, those are -2, -1, 0, 1, 2.
iii) Symbols of the orbitals for l = 1 sub-shell are p_x, p_y, p_z.
iv) Shape of the subshell l = 2 is double dumbel.
The maximum number of electrons that can occupy in this sub-shell is 10.

Question 5.
Write postulates and limitations of Bohr Hydrogen atomic model. (TS June 2018)
Answer:
Postulates :

1. Niels Bohr proposed that electrons in an atom occupy ‘stationary’ orbits of fixed energy at different distances from the nucleus.
2. When an electron jumps from a lower energy state (ground state) to higher energy state it absorbs energy or emits energy when such a jump occurs from a higher energy state.
3. The energies of an electron in an atom can have only certain values E₁, E₂, E₅…. that is, the energy is quantized.

Limitations :

1. Bohr’s model failed to account for splitting of line spectra of hydrogen atom into liner lines.
2. Bohr theory could not explain the Zeeman and Stark effect.

Question 6.
Explain Bohr’s model of hydrogen atom and its limitations. (March 2019)
Answer:
Niels Bohr proposed that,
a) electrons in an atom occupy stationary orbits of fixed energy (K, L, M, N,…) at different distances from the nucleus.

b) when an electron jumps from a lower energy state to higher energy state, it ab¬sorbs energy or emits energy when such a jump occurs from a higher energy state to lower energy state.

c) the energies of an electron in an atom can have only certain values E₁, E₂, E₃, ……… i.e. the energy is quantized. The states corresponding to these energies are called stationary states and the possible values of the energy are called energy levels.

d) the angular momentum of electron is multiple integral of \(\frac{L}{2 \pi}\).
∴ L = mvr = \(\frac{\mathrm{nh}}{2 \pi}\)
m = mass of electron ;
v = velocity of electron ;
r = radius of circular path;
h = plank constant

Limitations :

1. Bohr’s model failed to account for splitting of line spectra (Zeeman effect).
2. This model failed to account for the atomic spectra of atoms of more than one electron.
3. Bohr theory was not explained the quantisation of angular momentum of an electron.
4. It was not explained the formation of chemical bonds.

Question 7.
Explain four quantum numbers with an example. (AP SA-I; 2019-20)
Answer:
Each electron iii an atom is described by a set of three numbers called Quantum numbers.

1) Principal quantum number (n) :
It is used to know the size and energy of the main shell The values of ‘n’ are 1, 2, 3 …..
energy of the shell, n = 1 < energy of the Shell n = 2.

2) Angular momentum of quantum number (l) :
It is used to know the shape of a particular sub shell.
The values of ‘l’ are 0, 1, 2, 3
l = 0 = s orbital = spherical in shape
l = 1 = p orbital = dumbel in shape
l = 2 = d orbital = double dumbel Shape

3) i) Magnetic quantum number (m_l) :
It is used to describe the orientation of the orbital in space relative to the other orbitals in the atom.
The values of mt are – ‘l’ to ’+l’ including zero,

ii) Spin quantum number (m_s) :
It is used to know the orientation of the spins of electrons.
The values of ms are +½ and – ½.

Question 8.
How does Hund’s rule helps in writing electronic configuration of an atom? Explain with a suitable example. (TS June 2019)
Answer:
Hund’s rule :
According to this rule electron pairing in orbitals starts only when all available empty orbitals of the same energy are singly occupied.

This Hund’s rule helps in writing of electronic configuration of an element.

Example :

1. The electronic configuration of carbon (C) atom (Z = 6) is 1s² 2s² 2p⁶.
2. The first four electrons go into the Is and 2s orbitals.
3. The next two electrons go into separate 2p orbitals, with both electrons having the same spin.
   

Another example :

1. The electronic configuration of oxygen (₈O) is 1s² 2s² 2p⁴.
2. The first four electrons go into the 1s, 2s orbitals.
3. The next four electrons go into 2p orbits as 2 in 2p_x, 1 in 2p_y and 1 in 2p_z orbital.
   
4. Here pairing of electron in 2px starts after filling of electron in each 2p_x, 2p_y, 2p_z orbitals.
5. But electrons do not occupy like this
   

Question 9.
Your father asked you to go to the market and purchase an electric lamp. The shop-keeper displayed two lamps – one is violet and another is red. Which coloured lamp do you purchase to put in your bedroom? Support your choice of solution.
Answer:
Red has highest wavelength and violet has lowest wavelength. We know that relationship between energy as follows.
E = hv = h\(\frac{c}{\lambda}\)

h and c are remains constant.
∴ E ∝ \(\frac{1}{\lambda}\)

Energy is inversely proportional to wavelength. Red coloured light has lower energy and least intensity. So red coloured lamp is preferable as bed light.

Question 10.
Heisenberg contradicts Neils Bohr. Explain in what way he contradicts.
Answer:

• According to Bohr, electrons revolve around nucleus in definite paths or orbits. So the exact position of the electron at various times will be known to us.
• In order to explain Bohr’s postulate we have to know the velocity and exact position of electron.
• In order to find the position of electron we have to take the help of suitable light to find the position. As the electrons are very small, light of very short wavelength is required for this task.
• This short wavelength light interacts with the electron and disturbs the motion of the electron.
• Hence, it is not possible to find the exact position and velocity of electron simultaneously. This was stated by Heisenberg which is called Heisenberg’s principle of uncertainty.
• In this way Heisenberg contradicts Neils Bohr.

Question 11.
Explain Bohr-Sommerfeld model of an atom. What is the merit of this model? What are its limitations?
Answer:

• In an attempt to account for the structure of line spectra, Sommerfeld modified Bohr’s atomic model by adding elliptical orbits.
• While retaining the first of Bohr’s circular orbit as such, he added one elliptical orbit to Bohr’s second orbit, two elliptical orbits to Bohr’s third orbit, etc.
• Nucleus of the atom is one of the principal foci of these elliptical orbits because periodic motion under the influence of a central force will lead to elliptical orbits with the force situated at one of the foci.

Merit:
Bohr-Sommerfeld model is successful in accounting for the fine line structure of hydrogen atomic spectra.

Limitations :

1. This model failed to account for the atomic spectra of atoms of more than one electron.
2. It did not explain Zeeman and Stark effects.

Question 12.
In an atom the number of electrons in N-shell is equal to the number of electrons in K, L and M shells. Answer the following questions.
i) Which is the outermost shell?
Answer:
The outermost shell is p(n = 6).

ii) How many electrons are there in its outermost shell?
Answer:
Two electrons are there in outermost shell.

iii) What is the atomic number?
Answer:
Its atomic number is 56.

iv) Write the electronic configuration of the elements.
Answer:
The electronic configuration of element is
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s².

Question 13.
Explain the following electron configurations by using nl^x method.
a) 2p¹
b) 3d⁵
c) 4f⁹
d) 6s²
Answer:
In nl^x method n is the principle quantum number and l is the angular momentum quantum number and x is number of electrons. Now let us explain the following configurations
a) 2p¹ – It indicates that there is one electron in ‘p’ sub-shell of second orbit or shell.
b) 3d⁵ – It indicates that there are five electrons in ‘d’ sub-shell of third orbit or shell.
c) 4f⁹ – It indicates that there are nine electrons in ‘f’ sub-shell of fourth orbit or shell.
d) 6s² – It indicates that there are two electrons in ‘s’ sub-shell of sixth orbit or shell.

Question 14.
In an atom the number of electrons in L shell is equal to three times of K shell. Then answer the following.
1) Which is the outermost shell?
2) How many electrons are there in outermost shell?
3) What is the atomic number of element?
4) Write electronic configuration of element.
5) Write name of element.
Given that the number of electrons in L shell is three times of K shell.
Answer:
We know that number of electrons in K shell is 2.
Therefore number of electrons in L shell = 3 × 2 = 6

1. So the outermost shell is L.
2. The number of electrons in outermost shell is 6.
3. The atomic number of element is 8.
4. The electronic configuration of element is 1s² 2s² 2p⁴.
5. The element is oxygen.

Question 15.
We know that the electron configuration of copper is [Ar] 4s¹ 3d¹⁰. Is it against to Aufbau principle or not. If so, why is the configuration violated?
Answer:

• The atomic number of copper is 29. So its electron configuration should be [Ar] 4s² 3d⁴.
• But if one electron from 4s orbital jumps into 3d orbital, then copper gets half filled ‘d’ orbitals which gives stability to the atom.
• The energy difference between 4s and 3d is very less. So one electron can easily jump from 4s to 3d which gives half-filled 3d⁵ configuration.
• So, in order to get additional stability, Aufbau principle is violated i.e., electron enters the orbital of higher energy before the completion ortrital of lower energy.

Question 16.
Electronic configurations of following elements are written wrongly. Correct those configurations with proper explanation.

Answer:
1) The electron configuration of oxygen is 1s² 2s² 2p⁴ because the maximum number of electrons that can be filled in s orbital is 2 and so the extra electron should be entered in 2p.

2) The correct electron configuration of nitrogen is

The reason is that the pairing of electrons does not take place until each degenerate orbital is filled with one electron each (Hund’s principle).

3) The correct electronic configuration of scandium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ because after completion of 3p orbital electron enters in 4s because the energy of 4s orbital is less than 3d (Aufbau principle).

4) The correct electronic configuration of chromium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ 3d⁵. Because atoms having half filled or completely filled orbitals are more stable. So by transferring one electron from 4s to 3d the atom gets extra stability.

Question 17.
Here is set of quantum numbers. Do they form correct values of quantum numbers or not. If not, give reason.

The values l, m_l, m_s are not correct values for given ‘n’.
Answer:

• The maximum value for l is n – 1. If n = 3, then l takes values from 0 to 2. That is 0, 1, 2.
• m_l values depend on ‘l’. m_l take values from – l to + l including zero. So, the possible values for m7 may be from – 2 to + 2.
• Spin quantum number has only two values, i.e. and –\(\frac{1}{2}\) and \(\frac{1}{2}\). So \(\frac{1}{4}\) value is not possible.

Question 18.
Answer the following questions.
a) If n = 4, then what energy level does it represent?
Answer:
If n = 4, then it represents N energy level.

b) If n = 5, then what is the maximum value for l and why?
Answer:
If n = 5, then the maximum value of l for 4 because the maximum value for l is n- 1.

c) If l = 3, then what are the maximum possible values for m_l?
Answer:
Given l = 3.
Then possible values for m_l is 2l + 1.
∴ Maximum possible values = 2(3) +1 = 7

d) What is the number of electrons present in M energy level?
Answer:
For M energy level n = 3.
The maximum number of electrons in an orbit = 2n² = 2 × 3² = 2 × 9 = 18

Question 19.
Draw the shapes of s, p and d orbitals.
Answer:
s – orbital (Spherical) :

p – orbital (Dumbell) :

All P:

d – orbital (Double Dumbell):

Question 20.
Draw electromagnetic wave and label its parts.
Answer:

Question 21.
Draw the diagram of electromagnetic spectrum.
Answer:

These AP 9th Class Social Studies Important Questions 7th Lesson Industries in India will help students prepare well for the exams.

AP State Syllabus 9th Class Social 7th Lesson Important Questions and Answers Industries in India

9th Class Social 7th Lesson Industries in India 1 Mark Important Questions and Answers

Question 1.
Study the map given below and answer the following question. (SA-II : 2018-19)

Q : Where in Karnataka are the steel plants located?
Answer:
Vijayanagar and Bhadravathi are the two places has steel plants in Karnataka.

9th Class Social 7th Lesson Industries in India 2 Marks Important Questions and Answers

Question 1.
Draw a bargraph based on the given information. (SA-III : 2015-16)

Year	Production of cement (In million tonnes)
1970 – 71	25
1980 – 81	50
1990 – 91	100
2000 – 01	150
2010-11	210

Answer:

Question 2.
The pie charts below show the percentage of people employed in Agriculture. Industry and service sectors. Read the pie charts carefully to answer the question.

How did the pattern of employment change between 1972-73 and 2009-2010? (SA-II : 2018-19)
Answer:

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

9th Class Social 7th Lesson Industries in India 4 Marks Important Questions and Answers

Question 1.
Observe the ‘Pie Chart’ and answer the following questions. (SA-III : 2015-16)

Answer the following Questions.
1. What does the above given graph denotes?
2. What is the percentage of change in employment by industry when compare between 1972-73 and 2009-10?
3. Which sector generated highest employment in 2009-10?
4. Write any two occupations regarding service sector?
Answer:

1. The above graph explains % of employment in different sectors.
2. From 1972-73 to 20019-10 the change in employment in Industrial sector is from 11% to 22%.
3. Agricultural sector.
4. Doctor, lawyer, teacher, banking, commerce, communications etc. are the occupations in the sector.

Question 2.
“Industries are necessary for the development of a nation. It is also fact that industrial activities are increasing environmental problems” – Write your opinions on this matter in detail. (SA-III : 2016-17)
Answer:
Industries are necesary for the development of a nation by the following ways.

1. When goods made in factories and exported to other countries, we get revenue.
2. A few decades before, three-fourths of income from goods exported from manufacturing industries alone.
3. Even today, nearly two-third of goods exports is contributed by industries and particularly small industries.
4. Factory goods exported range from gems, jewellery, chemicals, cars, machinery, cashewnuts, etc.
5. 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.

At the same time industrial activities are increasing environmental pollution by the following ways.

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

Question 3.
Mixing of some poisonous substances in air, water and soil causes to ‘ecological crisis’ – give your suggestions to prevent this problems as a student. (SA-II : 2017-18)
Answer:
Pollution prevention is a major global concern because of the harmful effects of pollution on a person’s health and on the environment.
Suggestions:

1. Stop smoking or at least follow the “No smoking” sign.
2. Never use open fires to dispose of wastes.
3. Instead of using your cars, choose to walk or ride a bicycle whenever possible.
4. Adopt the BRs. of solid waste management, reduce, reuse and recycle.
5. Use eco-friendly or biodegradable materials instead of plastic.
6. Do not cause loud noises and unwanted sounds to avoid noise pollution.
7. Industries should use fuel with lower sulphur content.
8. Industries should strictly follow applicable government regulations on pollution control.

Conclusion :
Breathing is life. We know that we will survive without food for several weeks and without water for few days, but without oxygen, we will die in a matter of minutes.

The oxygen, the air we breathe sustains us. So, let us make today and every day a good day for everyone.

Question 4.

Read the above pie chart and answer the following questions. (SA-II : 2017-18)
1. What does the pie chart tell us?
2. Which sector provide the highest percentage of employment?
3. In which sector employment increased twice?
4. By 2009-10 which sector was the second piace in empioyment?
Answer:

1. Pie chart tells us the percentage of employment in different sectors from 1972-73 to 2009-10 years.
2. Agriculture sector provide highest percentage of employment.
3. In Industrial sector employment increased twice.
4. By 2009-10, the services sector is in second place in employment.

Question 5.
When people buy groceries, they may have their groceries packed in plastic bags, paper bags, or cloth bags they bring with them.
Which type of grocery bag is the best to help protect the environment?
a) Plastic
b) Paper
c) Cloth
Explain in what way your choice of bag can help protect the environment.
Answer:

• My choice is paper bag and cloth bag. Both are best to use.
• We should not use plastic bags as they are threat to environment.
• Plastic bags are not eco – friendly: They won’t decompose quickly, if you burn them also it will take time to mix with soil.
• Recently in Vijayawada, some areas of the city drowned in rainwater because all the sewage drains were filled with bunches of plastic bags.
• But paper and cloth bags will decompose in very short period and completely eco friendly.
• Paper bags made by wood pulp it may cause deforestation.
• Cloth bags made of cotton, quickly it decomposes.

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

Question 1.
Why are the infrastructure facilities important in establishing industries?
Answer:

• Building of roads, good transport facilities, power supply and telephone connections, etc. can be termed as infrastructural facilities.
• Factories need raw materials. These raw materials are to be transported to the factory sites. Hence good road ways and other facilities are needed.
• Factories need power to run machines. Hence all infrastructure facilities are needed.

Question 2.
Why are industries important?
Answer:
In industrial sector, the raw materials are worked upon by people and changed using tools and machines to produce a good that can be useful.
The importance of industries :
i) Industries provide a wide range of products :
There are plenty of goods made in factories. Ranging from paper and other stationery, fridges to cars, batteries, bulbs and other electrical appliances.

ii) Industries are expected to employ a large section of people looking for jobs :

1. Generating employment to work in factories is generally considered as one of the indicators of development and improvement of well being of people.
2. Employment in industries has increased from 11% in 1972-73 to 22% in 2009-10.

iii) Industries are important source of export incomes:

1. We earn a lot of foreign exchange by selling industrial goods to foreign countries.
2. Even today, nearly two-thirds of goods exported is contributed by industries.

Question 3.
What were the restrictions introduced by the government during the early years of industrialization?
Answer:

• Many industrial activities were allowed only for small producers. For example, production of cloth of specific quality was restricted to handlooms.
• Government made laws so that the large factory owners get prior permission or license to set up factories. This was done so that there would be better planning.
• The government regulated the quantity of goods produced by factories.
• The price at which they can be sold was also fixed.

All these restrictions were introduced keeping in view the welfare of the people.

Question 4.
Industrial policies of the early years became hindrance to the growth of industry. Explain.
Answer:

• Entrepreneurs were required to follow so many procedures and had to wait for many years to get the approval from the government offices.
• Licenses were not given to the most efficient producers.
• The selection was biased in favour of people with political connections and the economically powerful.
• All this discouraged new entrepreneurs who would work with latest technology available.
• Further control on prices led to shortage of goods. E.g.: Scooters.
• Such shortages were common for important basic goods like coal and cement, which in turn caused a lot of delay in production of other goods.
• Another problem was lack of quality of some of goods.
• There were restrictions on the import and export of industrial goods including machinery and raw materials.
• Prices were laid down by the government and the producers had to sell only at that price.
  So the above restrictions acted as hindrance to the growth of industry.

Question 5.
Write about the impact of industrial policies.
Answer:
The following are the impacts of industrial policies of government.
i) Rise in the number of industrial units:
Today nearly 2 lakh large factories and 3 crore small factories are operating in India.

ii) Employment has increased but less than expected:
Both small and large scale employ nearly about one-fifth of India’s 460 million workers.

iii) Low salaries and less working conditions:
A large section of workers are employed in small units which generally pay very low salary and devoid of workers safety conditions and health benefits.

iv) Production of factory-based goods has increased:
Establishment of basic industries resulted in increased production of factory based goods.

1. The production of coal and lignite has increased from 32 million tons in 1950-51 to 571 million tons in 2010-11.
2. The production of steel has increased from 10 million tones in 1980-81 to 70 million tons in 2010-11.
3. There was also a significant increase in the production of crude oil and cement etc.

v) Increase in environmental problems, land conflicts and pollution:
These industries release a lot of waste materials into the atmosphere and into the tanks and wells causing lots of air pollution and damaging water resources. The air pollution is causing skin diseases and respiratory diseases.

Question 6.
At the time of independence what were the objectives that were desired to be achieved through industrialization?
Answer:

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

Question 7.
Where should the sugar and jaggery mills be ideally located?
Answer:
The sugar and jaggery milis should be ideally located near the crop grown areas.

Question 8.
Where would it be economically viable to set up the cement manufacturing units?
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 9.
Name the important centres of cotton textiles in Gujarat.
Answer:
Ahmedabad, Vadodara, Surat, Rajkot and Porbandar.

Question 10.
Where are the silk textile industries located in Jammu and Kashmir?
Answer:
In Baramula, Srinagar and Anantanag.

Question 11.
What are the basic requirements of industrialization?
Answser:

• Industrialization means to develop a large number of different factories.
• For industrialization, we have certain basic requirements.
• They are machines, electricity, minerals and ores and transport facilities.

Question 12.
What factors influence the selection of an industrial location?
Answer:

• Industrial locations are complex in nature.
• These are influenced by raw material labour, capital, power, and market, etc.
• It is rarely possible to find all these factors available at one place.
• So industries are located where these factors even can be arranged at lower cost.

Question 13.
What is an agrobased industry?
Answer:
The industries which are based on agricultural products are called ‘agrobased industries’.

Question 14.
Why do you think cotton textile industry is concentrated in Maharashtra and Gujarat?
Answer:

• Many factors support the concentration of cotton textile industry in Maharashtra and Gujarat.
• Availability of raw cotton, market, transport including accessible port facilities, moist climate etc. are some factors.
• Apart from these, availability of abundunt electricity at cheap prices and availability of skilled and unskilled labour in abundance add to those factors.
• These places also have investment supports from Banks and international market demands.
• Above factors help the flourishing of cotton textile industry in Maharashtra and Gujarat.

Question 15.
Read the following passage and answer the questions given below.

Challenges faced by the industry include stiff competition in the international market from synthetic substitutes and from other competitors like Bangladesh, Brazil, Philippines, Egypt and Thailand. However, the internal demand has been on the increase due to the Government policy of mandatory use of jute packaging. To stimulate demand, the products need to be diversified. In 2005, National Jute Policy was formulated with the objective of increasing production, improving quality, ensuring good prices to the jute farmers and enhancing the yield per hectare. The main markets are U.S.A., Canada, Russia, United Arab Republic, U.K. and Australia. The growing global concern for environment friendly, biodegradable materials, has once again opened the opportunity for jute products.

1) What is the industry mentioned in the above passage?
Answer:
Jute industry.

2) What are the challenges faced by the industry?
Answer:
Challenges faced by the industry include stiff competition in the international market from synthetic substitutes and from other competitors like Bangladesh, Brazil, Philippines, Egypt and Thailand.

3) When was National Jute Policy formulated?
Answer:
In 2005.

4) Name the main markets mentioned in the passage.
Answer:
USA, Canada, Russia, United Arab Republic, UK and Australia.

5) To stimulate demand, the products need to be
Answer:
diversified.

Question 16.
Discuss what is meant by the word “basic”? What are the basic necessities for industries?
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, telephone, etc.

Question 17.
Today West Bengal is the dominant state in Jute Industry. How is it able to become like that?
Answer:

• Most Jute mills in India are in West Bengal, mainly along the banks of the Hugli river 98 km long and 3 km wide.
• Hugli basin is in proximity of Jute producing areas, inexpensive water transport, supported by a good network of railways, roadways and waterways to facilitate movement of raw materials to mills.
• Abundant water for processing of raw jute, cheap labour from West Bengal, Bihar, Odisha and Uttar Pradesh.
• Kolkata provides banking, insurance and port facilities for export of jute goods.
• It provides direct or indirect employment to more than 40 lakh people.

Question 18.
Name the problems that are faced in the Iron and Steel industry?
Answer:

• It needs huge capital investment, which is difficult for developing country India.
• Indian technology is now far behind the advanced countries.
• Low per capita productivity and low potential utilization are to be addressed.
• Even at a low per capita consumption, demand for our production is not sufficient.
• Now we are importing iron and steel by spending precious foreign exchange.
• All the above problems needed to be solved.

Question 19.
Locate the following industrial cities on the outline map of India. City

City	Industries Concentrated
Jamshedpur	Iron and Steel company
Ahmedabad	Textile industry
Mumbai	Textile, oil refinery, fertilizers, etc.
Visakhapatnam	BHPV, Steel Plant, Ship building, etc.
Chennai	Cement, Cotton, Railway coaches, etc.
Rourkela	Iron and Steel industry
Kanpur	Leather industry
Madurai	Cotton textile industry
Luduiana	Leather industry
Varanasi	Diesel locomotives

Question 20.
Observe the following map and answer the questions given below.

1) Where do you find both cotton and woollen textiles?
Answer:
In Ahmedabad and Kanpur.

2) What is the South India state famous for silk textiles?
Answer:
Karnataka.

3) Name the important centres of cotton textiles in Gujarat.
Answer:
Ahmedabad, Vadodara, Surat, Rajkot and Porbandar.

4) Which type of textile industries are in major position in Maharashtra?
Answer:
Cotton textile industries.

5) Where are the silk textile industries located in Jammu and Kashmir?
AIn Baramula, Srinagar and Anantanag.

Question 21.
Observe the following map.

Now answer the questions given below.
1) What are the minerals mentioned in the map?
Answer:
Iron ore, manganese, bauxite and mica.

2) In which states do you find iron ore mines?
Answrr:
Maharashtra, Karnataka, Odisha and Chattisgarh.

3) What are the iron ore ex-porting ports mentioned in the map?
Answer:Visakhapatnam, Managalore, Marmagao and Paradwip.

4) Where can we find mica in Andhra Pradesh?
Answer:
In Nellore.

5) What is the mineral found in Rajasthan?
A. Mica.

Question 22.
Observe the following map.

Now answer the questions given below.
1) Which state is Raniganj coal mine located in?
Answer:
West Bengal

2) Where is the coal field located in Tamilnadu?
Answer:
Neyveli

3) Name the important coal mine of Telangana.
Answer:
Singareni

4) What is the coa! field that belongs to Chattisgarh?
Answer:
Korba

Question 23.
What steps are to be taken to reduce the problems of pollution?
Answer:

• We should stop effluent flow into water bodies.
• Provide safety drinking wafer to the affected villages.
• Continuous vigilance in discharge of effluents.
• Medical care to pollution victims.
• Cancellation of licence to pollution causing industries.

Question 24.
What measures would you suggest to overcome the problems of Textile Industry?
Answer:

• Care should be taken to increase the supply of raw material.
• Obsolute machinery which resulting in low productivity and inferior quality should be replaced.
• Government should provide adequate power to textile industry.
• Care should be taken that textile industry shall not lost in the stiff competition with power loom and synthetic fiber products.
• Many textile mills are sick, government should help them run properly.

Question 25.
What suggestions would you make to improve jute industry?
Answer:

• The best way to solve the problems of jute industry is to increase production.
• There is an urgent need to replace the old machinery.
• Jute mills are needed to be modernized.
• New Jute products are to be developed.
• The product range of jute is to be diversified.

These AP 9th Class Biology Important Questions 1st Lesson Cell its Structure and Functions will help students prepare well for the exams.

AP State Syllabus 9th Class Biology 1st Lesson Important Questions and Answers Cell its Structure and Functions

9th Class Biology 1st Lesson Cell its Structure and Functions 1 Mark Important Questions and Answers

Question 1.
What are the cell organelles present in a cell?
Answer:
The cell organelles present in a cell are endoplasmic reticulum, golgi apparatus, lysosomes, mitochondria, ribosomes, plastids and vacuoles.

Question 2.
What is the role played by cell wall in plant cells?
Answer:

• Cell wall excretes and inward wall pressure to resists the outward directed pres¬sure exerted by cell sap.
• So, the plant cells can withstand much greater changes in surrounding medium than animal cells.

Question 3.
What is cell theory?
Answer:

• Cell theory was proposed by Schleiden and Schwann.
• All living organisms are composed of cells and product of cell.
• All cells arise from pre-existing cells.

Question 4.
Write one precaution while observing nucleus in cheek cells.
Answer:

• Do not scrap the cheek too hard as it may injure the buccal mucosa.
• Excess stain should be drained off.

Question 5.
Name the colourless plastids in plants.
Answer:
Leucoplasts

Question 6.
Write the name of the plastids that are responsible for different colours in flowers and fruits.
Answer:
Chromoplasts

Question 7.
Mention the cell organell that is called “Protein factories”.
Answer:
Ribosomes

Question 8.
Name the cell organell that is known as “suicidal bags of the cell”.
Answer:
Lysosomes.

Question 9.
Write the main function of Smooth Endoplasmic Reticulum.
Answer:
The SER helps in the manufacture of fat molecules or lipids important for cell function.

Question 10.
What happens if Endoplasmic reticulum is destroyed in the cell?
Answer:
The transportation of substances from one part to another part of the cell will not occur.

Question 11.
What is the site of protein synthesis in the cell?
Answer:
Ribosomes

Question 12.
Write some examples for prokaryotic cells.
Answer:
Bacterium, Cyanobacteria and Blue green algae are examples for prokaryotic cells.

Question 13.
Write the unique feature seen in plant cells.
Answer:
Presence of cell wall is the unique feature seen in plant cells.

Question 14.
Name the selectively permeable membrane that covers the cell.
Answer:
Plasma membrane

Question 15.
What is an enzyme?
Answer:
An organic catalyst which catalyses a reaction within a cell.

Question 16.
Who coined the term ’Cytoblast’ and why?
Answer:
Schleiden called the nucleus as cytoblast, because he thought that new cells were created from the nucleus.

Question 17.
What is the site of cellular respiration?
Answer:
Mitochondria

Question 18.
What are vacuoles and write their function.
Answer:
Vacuoles are the fluid filled sac like structures present in the cytoplasm. They store solid or liquid contents.

9th Class Biology 1st Lesson Cell its Structure and Functions 2 Marks Important Questions and Answers

Question 1.
What is the difference between protoplasm and cytoplasm?
Answer:

• There is a fluid present inside the cell.
• For a long time it was believed that the essence of life was stored in the fluid.
• Hence the fluid was named as protoplasm, which means life fluid.
• When it became clear that the fluid is basically a medium in which various particles and membranes float, protoplasm was renamed as cytoplasm.

Question 2.
Take one grape fruit and place it in salt solution, Note the observations.
Answer:

• I take one grape fruit and placed it in salt solution.
• After sometime I observed that the fruit shrunk.
• This is because of loss of water inside the fruit, it comes out into salt solution.
• During this, the process of osmosis takes place.

Question 3.
Collect some parts of plants like, orange, beetroot, raddish, drumsticks, lady’s fin-ger, Jasmine, etc. and put a tick mark if you find the listed plastids present in them.
Answer:

Question 4.
Why animals depend upon plants for food?
Answer:

• Animal cells do not have chloroplasts.
• Chloroplast trap the energy from sunlight.
• It converts solar energy to chemical energy which takes place during photosynthesis.
• During the process of photosynthesis food materials are formed.
• Due to lack of chloroplasts animals are unable to prepare their own food.
• So, animals depend on plants for food.

Question 5.

Cell organelle	Function
Nucleus	Nucleus regulates and controls all the functions of a cell and determines the characteristics of the organism.
Endoplasmic reticulum	1. It serve as channels for the transport of materials within the cell.
	2. It also functions as a cytoplasmic framework for various biochemical activities.
Golgi Apparatus	It package various substances. Proteins are altered slightly by golgi apparatus.
Lysosomes	It participates in intracellular digestion. It destroys the cell contents.
Mitochondria	It produces energy through cellular respiration.
Plastids	These are responsible for the colour of the plant cell.
A. Chloroplasts	These trap solar energy and convert this to chemical energy during photosynthesis.
B. Chromoplasts	These are responsible for the coloured fruits, flowers.
C. Leucoplasts	These are colourless, stores carbohydrates, oils and proteins.

Study the table and answer the questions.
1) Name the cell structure that helps in photosynthesis.
2) Name the cell organell that participates in intercellular digestion.
Answer:

1. Chloroplasts
2. Lysosomes

Question 6.
What happens if stomata are closed with paraffin wax?
Answer:

• Stomata helps in exchange of gases in leaf.
• If the stomata are closed with paraffin wax gaseous exchange will not takes place.

Question 7.
What questions do you pose to know more details about plasma membrane?
Answer:

1. How can you say that plasma membrane is also known as selectively permeable membrane?
2. Name the substances that can pass through the plasma membrane.
3. Give examples for selectively permeable membrane.

Question 8.
Write the main function of the cell wall.
Answer:

• The cell wall is tough but flexible porous layer that gives a definite shape to the cell.
• It provides protection to the cell from the external shocks.

Question 9.
Venu is asking his teacher about different functions of cell organells of Eukaryotic cell. What questions he would ask to his teacher ?
Answer:

1. Prokaryotic cells devoid of nucleus . Why?
2. Are the cell organells of same size in all the higher animals?
3. Why lysosomes are called suicidal bags of the cell?
4. What happens if cell wall is not present in plant cell?

Question 10.
Write about plastids.
Answer:

• Plastids are present only in plant cells.
• Plastids mainly of two types. 1. Chromoplasts (coloured) and leucoplasts (colourless).
• Chloroplasts are the type of chromoplasts present only in plants.
• The primary function of a chloroplast is to trap the energy of sunlight and transform it to chemical energy thus helping to carryout photosynthesis.
• Chromoplasts are responsible for having various colours of fruits, flowers and leaves.
• Leucoplasts are used to store starch, oil and proteins.

Question 11.
Write differences between plasma membrane and cell wall.
Answer:

Plasma membrane	Cell wall
1. Made up of lipid and proteins.	1. Made up of cellulose.
2. It is Living.	2. It is Dead.
3. Present in both plant and animal cell.	3. Found exclusively in plant cells.

Question 12.
What is the reason for colour change in tomatoes? (green – white – yellow – red)
Answer:
1) Plastids are responsible for colour change in tomatoes.

2) Plastids are of three types :
1. Chromoplasts (coloured)
2. Leucoplasts (colourless)
3. Chloroplasts (green)

3) All the three plastids have the capacity to change from one to another.

4) As the young tomatoes mature we see green, white, yellow and red coloured tomatoes.

Question 13.
Draw a neat and labelled diagram of nucleus.
Answer:

Question 14.
Draw a neat and labelled diagram showing L.S of mitochondria.
Answer:

Question 15.
Draw a neat and labelled diagram showing the structure of chloroplast.
Answer:

Question 16.
Draw a neat and labelled diagram of Endoplasmic Reticulum find in electron microscope.
Answer:

Question 17.
What is the function of a nucleus in a cell?
Answer:

• The nucleus plays a vital role in the cell.
• It controls all functions of the cell. It controls cell division.
• Nucleus contains chromosomes. These chromosomes contain DNA and proteins.

Question 18.
“Cell is the structural and functional unit of life” – How?
Answer:
a) A cell is capable of independently carrying out all necessary activities of life,
b) Hence, it is called the structural and functional unit of life.

Question 19.
What is Protoplasm? Who coined this term and when?
Answer:
a) The living fluid substance of the cell is called “Protoplasm”
b) Purkinje in 1839 coined the term protoplasm.

Question 20.
Name the smallest and largest known cells in this world?
Answer:
a) The smallest known cells is pneumonea cell. It is about 0.1 m in diameter.
b) An Ostrich egg cell is the largest known cell. It is 170 x 135 mm approximately.

Question 21.
What will happen to the size of the cell if it is placed in such solutions which vary in their concentrations.
a) When placed in Hypotonic solution?
b) When placed in Isotonic solution?
Answer:

• When a cell is placed in Hypotonic solution (dilute solution), water enters into the cell. Hence the cell swells up.
• When a cell is placed in Isotonic solution (same concentration), there is no movement of water. Hence the cell will stay the same size.

Question 22.
“A cell is a building unit of an organism”. Do you agree with this statement? If yes, explain why.
Answer:

• I agree with the above statement.
• A cell is a building unit of an organism because it is responsible for building the entire body of an organism.

Question 23.
What is Osmosis?
Answer:
Osmosis is the passage of water or any solvent from a region of its lower concentration to a higher concentration through a semi permeable membrane.

Question 24.
What are genes? What is their function?
Answer:
Genes are the segments of DNA present on the chromosomes. These are the hereditary units which are transmitted from one generation to another by chromosomes.

9th Class Biology 1st Lesson Cell its Structure and Functions 4 Marks Important Questions and Answers

Question 1.
Write a short note on the Golgi apparatus.
Answer:

• Camillo Golgi first observed the golgi bodies in 1898.
• This is made up of several membranes.
• These membranes create sac-like structure around which many fluid-filled vesicles abound.
• The proteins and other substances produced in the ribosomes reaches the golgi body through these vesicles.
• This organelle package various substances before Ciste they are transported to other parts of the cell. _
• The number of golgi bodies varies from cell to cell. Golgi apparatus
• They are large in number in those cells that secrete hormones and enzymes.

Question 2.
Write about mitochondria.
Answer:

• Mitochondria are small, spherical or cylindrical in shape.
• They are 2-8 micron long and about 0.5 micron wide.
• It is about 150 times smaller than the nucleus.
• 100 – 150 are present in each cell.
• They are made of a double-membrane
• The inner membrane of the wall protrudes into the interior in folds and forms cristae.
• The space between cristae is known as the matrix.
• They are responsible for cellular respiration.
• Energy generated and stored in mitochondria.
• Hence they are also called as cell’s power house.

Question 3.
Write a note on Cytoskeleton.
Answer:

• Endoplasmic Reticulum (ER) is one of the important cell organelle.
• It extends all over the cell, so it is also called as cytoskeleton.
• It is responsible for the transport of substances from one part of the cell to another.

• RER has ribosomes on its surface which are caused for protein manufacture.
• The SER helps in the manufacture of fat molecules.
• Invertebrate liver cells SER plays a crucial role in detoxifying many poisons and drugs.

Question 4.
How could you appreaciate the function of nucleus in a cell?
Answer:

• Nucleus is the most prominent one of all cell organelles.
• This is also known as cell’s control room.
• It was named by Robert Brown in 1831.
• All cells have nucleus except a few cells.
• In mammal red blood cells and phloem sieve tube in plants nucleus is absent.
• It regulates and controls all the functions of the cell.
• It determines the characteristics of the organism.
• It is the barrier of all genetic information.
• It involved in the process of cell division.
• If there is no nucleus in the cell, growth of organism not takes place.

Question 5.
Draw the diagram of nucleus and label it.
Answer:

Question 6.
Why the colouring fruits or vegetables changes? Support your answer.
Answer:

• In plants plastids are responsible for the colouring of fruits and vegetables.
• There are 3 types of plastids present in plants.
• Chloroplasts are responsible for green colour.
• Chromoplasts are responsible for different colours, i.e., orange, yellow, red etc.
• Leucoplasts are responsible for white colour.
• These plastids have the capacity to change from one form to another.
• E.g. : Young tomatoes are white in colour as they mature they turn to green and then to red in colour.

Question 7.
In what way different colours in flowers helpful to bio-diversity?
Answer:

• We can easily identify their species at a glance.
• By having different colours plants attracts insects for pollination, for their propagation.
• By having different colours plants appeal to the aesthetic sense of man, immense pleasure and happiness.
• This is useful in the propagation of plants by the human beings.
• Generally butterflies are known as the pollinators, but in fact they are the indicators of the health of an ecosystem.

Question 8.
Describe endoplasmic reticulum.
Answer:

• The network or membranes present in the cytoplasm for the transport of substances
  from the one part of the cell to another is known as endoplasmic reticulum.
• Endoplasmic reticulum is of two types.
  i) Rough endoplasmic reticulum and
  ii) Smooth endoplasmic reticulum.
• Endoplasmic reticulum having ribosomes on their surface is known as rough endoplasmic reticulum.
• The rough endoplasmic reticulum is the sites of protein synthesis.
• Ribosomes are absent in smooth endoplasmic reticulum and is involved in lipid synthesis.
• One function of the endoplasmic reticulum is to serve as channels for the transport of materials within the cytoplasm.
• It also function as a cytoplasmic framework providing a surface for some of the biochemical activities of the cell.

Question 9.
Observe the following slides under the microscope and draw their pictures. Write the cell organelles in them.
Answer:

Organelles present in Amoeba :
Nucleus, contractile vacuole, food vacuole etc.

Organelles present in Euglena :
Nucleus, chloroplasts, contractile vacuole, reservoir, paraflagellar body, endosome etc.

Cell organelles present in Paramoecium :
Anterior and posterior contractile vacuoles, micronucleus, macronucleus, cytostome, cytopyge, food vacuole etc.

Question 10.
Collect the names and photographs of scientists helped for the development of cell biology. Give brief note on them.
Answer:

• 1632 – 1723 Antonie Van Leeuwenhoek constructed simple microscope and draws protozoa, verticella from rain water and bacterium from his mouth.
• 1665 Robert Hooke discover cells in Cork, then in living plant tissues using an early compound microscope.
• In 1831 Robert Brown discovered nucleus. In 1839 Purkinje coined the term protoplasm.
• In 1839 Theodar Schwann and M.J. Schleiden proposed cell theory.
• 1855 – Rudolf Carl Virchow observed cell division.
• 1931 – Earnest Ruska built first transmission electron microscope.
• 1953 – Watson & Crick made their first announcement on the double helix structure of DNA.
• Albert Claude, father of cell biology awarded Nobel prize for Physiology (Medicine) in 1974.
• 1981 – Lynn Margulis published symbiosis in cell evolution detailing the endosymbiotic theory.

9th Class Biology 1st Lesson Cell its Structure and Functions Important Questions and Answers

Question 1.
What happens if there are no mitochondria in eukaryotic cell?
Answer:
If Mitochondria are absent in Eukaryotes, the energy required to perform all cellular activities will not be released. Hence, all the biological activities occurring in the cell will be stopped ultimately. This leads to the death of the eukaryotic cell.

Question 2.
What are the differences between protoplasm and cytoplasm?
Answer:

• Protoplasm is the content of the cell including the cell membrane, cytoplasm and the cell nucleus.
• Cytoplasm is the jelly like substance surrounding the nucleus within the cell membrane. The cytoplasm contains the cell organelles like mitochondria, ribosomes, etc.

Question 3.
a) Identify the figure and write the parts.
b) Write a short note on the above figure.

Answer:
a)

1. Matrix
2. Cristae
3. Inner membrane
4. Outer membrane

b)

1. The above shown cell organelle is mitochondria.
2. It performs cellular respiration and releases energy required for all cellular activities.
3. Mitochondria is also known as “Power house of the cell”.
4. Mitochondria are made up of a double membrane wall. The inner membrane of the wall protrudes into the interior in folds and forms structures called cristae.
5. The space between cristae is filled with a fluid known as the matrix.

Question 4.
Write the functions of the following cell organelles.

Answer:

• Mitochondria performs cellular respiration. They release energy for all biological activities of the cell.
• Chloroplasts trap the solar energy and helpful in photosynthesis through which plants derive their food.

Question 5.
a) Draw a neat labelled diagram of a plant cell.
b) Write the functions of endoplasmic reticulum.
Answer:
a)

b) Functions of Endoplasmic Reticulum :

1. The ER is to serve as channels for the transport of materials between various regions of the cytoplasm or between the cytoplasm and the nucleus.
2. It is the site of many bio – chemical activities in the cell.
3. It helps in the synthesis of proteins and lipids.
4. In vertebrate liver cells, SER plays a crucial role in detoxifying many poisons and drugs.

Question 6.
What does the modern cell theory propose?
Answer:
i) All living organisms are composed of cells and products of the cells.
ii) All cells arise from the pre existing cells.

Question 7.
What happens if lysosomes are absent in the cell?
Answer:
The materials that need to be destroyed are sent to lysosomes. They release the enzymes and digest them. If lysosomes are not present, the harmful substances which are dangerous to the cell would not be destroyed. The cell may die.

Question 8.
Name the chemical substance used in cheek cell lab activity.
Answer:
Methylene blue

Question 9.
Describe the nucleus of cell with the help of a well labelled diagram.

Answer:

• The membrane that encloses the nucleus and separates it from contents of cytoplasm is known as nuclear membrane.
• The entire genetic material of the cell is found in the nucleus.
• The nucleus has fluid like substance called nucleoplasm.
• In the centro of the nucleus, we can see a round shaped structure called nucleolus.
• Nucleus controls and regulates all the activities of the cell.
• Nucleus is closely involved in the process of cell division.

WorkBook Part

1. Write an activity to observe the nucleus in cheek cells.
2. Write a brief notes about mitochondria with help of the diagram.
3. Draw the diagram of Nucleus and label its parts.
4. Write name of the following figure and write its parts.
5. Write the name of the following figure and write its parts.

These AP 9th Class Social Studies Important Questions 14th Lesson Democratic and Nationalist Revolutions 19th Century will help students prepare well for the exams.

AP State Syllabus 9th Class Social 14th Lesson Important Questions and Answers Democratic and Nationalist Revolutions 19th Century

9th Class Social 14th Lesson Democratic and Nationalist Revolutions 19th Century 1 Mark Important Questions and Answers

Question 1.
How do you appreciate the Cavours role in unification of Italy? (SA-II : 2017-18)
Answer:
Cavour’s work in the Unification of Italy is appreciable.
He unify the regions of Italy through a tactful diplomatic alliance with France and he worked neither a revolutionary nor a democrat.

Question 2.
Who formed ‘Young Italy’? Why? (SA-I : 2019-20)
Answer:
Young Italy was formed by Joseph Mazzini.
The main reason is to unified Italy and would touch off a European wide revolutionary movement.

9th Class Social 14th Lesson Democratic and Nationalist Revolutions 19th Century 2 Marks Important Questions and Answers

Question 1.

Read the map given above and answer the following questions. (SA-III : 2016-17)
1. Mention the names of any two islands that are shown in the map?
2. The states which are shown above, are parts of which country now?
Answer:
1. Corsica, Sardinia, and Sicily.
2. At present the states which are shown in map are related to the country Italy.

Question 2.
What were the political, social, and economic ideas supported by the liberals in France in the beginning of 19th century? (SA-I : 2018-19)
Answer:
Political, social, and economic ideas supported by liberals.
→ Freedom for the individual.
→ Equality of all before the law.
→ Concept of government by consent.
→ End of autocracy and privileges of the church.
→ Constitution and representative government through parliament.
→ Inviolability of private property.

Question 3.
With reference to the Unification of Germany, answer the following questions. (SA-I : 2019-20)
i) Which country took leadership for Unification of Germany?
Answer:
Prussia.

ii) With what 3 countries did Bismarck go to war to achieve German unification?
Answer:
Denmark, Austria, and France.

9th Class Social 14th Lesson Democratic and Nationalist Revolutions 19th Century 4 Marks Important Questions and Answers

Question 1.
The French women fought for which rights ? in the context of India, were the women given all these rights? Write your analysis. (SA-I : 2018-19)
Answer:
French women fought for Right to vote, Right ot contest to Legislature, and Right to capture political power.
Then in the context of India all Indian women who are eligible, get all the above rights. Even though in the issue of gaining above the rights some negligence is there in India.

1. Representation of women in legislature is very less.
2. Women Reservation bill is still not approved in Lok Sabha.
3. Very less women are in political posts.

Question 2.
Describe the process of Italian Unification in 19th Century. (SA-II : 2018-19)
Answer:
Unification of Italy :
I Stage :
In 1830s Guiseppe Mazzini had sought to put together a coherent programme for a Unitary Italian Republic.
He had also formed a secret society called Young Italy for the dissemination of his goals.

II Stage :

• Prime Minister Cavour who led the movement to unify the regions of Italy, was neither a revolutionary nor a democrat.
• Through a tactful diplomatic alliance with France, he defeated Austria.

III Stage :

• Under the leadership of Garibaldi, a large number of Red Shirts army joined the fray.
• In 1860 they marched into South Italy and the kingdom of the Two Sicilies and succeeded in winning the support of the local peasants in order to drive out the Spanish rulers.

IV Stage :
Finally, Victor Emmanel II occupied Rome, and Unification of Italy completed. In 1871 Victor Emmanuel II was proclaimed king of unified Italy.

9th Class Social 14th Lesson Democratic and Nationalist Revolutions 19th Century Important Questions and Answers

Question 1.
Write about Jacobins constitution.
Answer:

• Under the Jacobian constitution, all people were given the right to vote and the right to insurrection.
• The constitution stated that the Government must provide the people with work or livelihood.
• The happiness of all was proclaimed as the aim of government.
• The government abolished slavery.
• Hence the Jacobians was the first genuinely democratic constitution in history.

Question 2.
How did nationalism and the idea of the nation-state emerge?
Answer:

• A nation state was one in which the majority of its citizens came to develop a sense of common identity and shared common history.
• This commonness did not exist from time immemorial, it was forged through struggles, through the actions of leaders and the common man.
• The French revolution gave the term “nation” its modern meaning.
• A nation is not the territory but the people who make it.
• The French revolution gave the meaning of sovereignty that the people constituting the nation are the source of all power and authority.
• Government is answerable to its people.

All these ideals led to the formation of the nation-states.

Question 3.
Discuss the importance of language and popular traditions in the creation of national identity.
Answer:

• Language and popular traditions are important in the creation of national identity.
• National identity means people feeling that they belong to a nation irrespective of their caste, religion, colour, etc.
• The language makes people identify themselves as a one race or a nation.
• Also, the popular traditions such as Roman culture and tradition etc. easily attracted the people and strengthened the national integrity.

Question 4.
In what ways do you think could the French revolutionaries help the other people of Europe to become nations?
Answer:

• I think the French revolutionaries could help the other people of Europe to become nations.
• The French revolutionaries fought for the principles of liberty, equality, and fraternity.
• They proved that France was not just a territory but the French people.
• The revolutionaries further declared that it was the mission and the destiny of the French nation to liberate the peoples of Europe from despotism, in other words, to help other people of Europe to become nations.

Question 5.
Do you think the anti-Nizam movement was a nationalist movement like French revolution? Compare the similarities and differences between the two movements.
Answer:

• Anti-Nizam movement was a nationalist movement like French Revolution.
• Both these were against the rulers at that time.
• The revolutionaries in French revolution became violent at times, whereas the activists in anti-Nizam movements suffered a lot in the hands of Nizam army.

Question 6.
Why do you think liberal democracy was reluctant to give right to vote to women and propertyless men?
Answer:

• Liberals did not ensure universal right to vote for all the people.
• Right to vote and get elected was given only to property – owing men.
• Men without property and all the women were not given any political rights.

Question 7.
In what ways were the liberals different from the conservative monarchists and how were they different from the radical poor?
Answer:

• Liberals believe that government should work by consent of people.
• Liberals believe people should have equal freedom and all are equal before law.
• Constitutional Monarchists believe in privilege of rich landlords and powers of monarch.
• They want to use modernization as a tool to increase control over the state.
• Radical poor wanted to bring change in the order with a reign of terror.

Question 8.
Why do you think were defeated by the conservatives?
Answer:

• Liberals talked of political democracy only and no equality was propogated.
• They did not even supported universal franchise and equality before law.
• But conservatives used modernization to have greater control overstate.
• They wanted to abolish serfdom and federalism and installation of modern army, dynamic economy, etc.

Question 9.
Read the following passage and answer the questions given below.

Linder the Jacobin constitution, all people were given the right to vote and the right of insurrection. The constitution stated that the government must provide the people with work or livelihood. The happiness of all was proclaimed as the aim of government. Though it was never really put into effect, it was the first genuinely democratic constitution in history. The government abolished slavery in the French colonies. Napoleon’s rise to power was a step backward. However, though he destroyed the Republic and established an empire, the idea of the republic couldn’t be destroyed. After the defeat of Napoleon, the old ruling dynasty of France was restored to power. However, within a few years, in 1830, there was another outbreak of revolution. In 1848, the monarchy was again overthrown though it soon reappeared. Finally, in 1871, the Republicwasagain proclaimed.

1) What was the first genuinely framed constitution in the world?
Answer:
Jacobin’s constitution was the first genuinely framed constitution in the world.

2) Why was the Jaccobians constituion called the first genuinely framed constitution?
Answer:
1) The Jacobin’s constitution gave the right to vote to all citizens.
2) The constitution stated that the government must provide the people with work. Hence it was called the first genuinely framed constitution in the world.

3) Who was the dictator that ruled over France during early 19th century?
Answer:
Napoleon.

4) When were the revolutions occurred in France in the early 19th century?
Answer:
In 1830 and 1848, the France experienced revolutions.

5) When was the Republic proclaimed in france?
Answer:
The Republic was proclaimed in France in 1871 A.D.

Question 10.
Read the following passage and answer the questions given below.

The Habsburg Empire that ruled over Austria-Hungary, for example, was a patchwork of many different regions and peoples. It included the Alpine regions -the Tyrol, Austria, and the Sudetenland – and Bohemia, where the aristocracy was predominantly German-speaking. It also included the Italian-speaking provinces of Lombardy and Venetia. In Hungary, half of the population spoke Magyar while the other half spoke a variety of dialects. In Galicia, the aristocracy spoke Polish. Besides these three dominant groups, there also lived within the boundaries of the empire, a mass of subject, peasant peoples -Bohemians and Slovaks to the north, Slovenes in Carniola, Croats to the south, and Roumans to the east in Transylvania. Such differences did not easily promote a sense of political unity. The only tie binding these diverse groups together was a common allegiance to the emperor.

1) Name the Alpine regions is the Habsburg Empire.
Answer:
The Tyrol, Austria and the Sudetenland, and Bohemia were the Alpine region.

2) In which language did the aristocracy speak in the Alphine region?
Answer:
The Aristocracy in the Alphine spoke in German.

3) What were the Italian speaking provinces of the Habsburg Empire?
Answer:
Lombardy and Venetia were Italian provinces.

4) A mass of subject peasant people lived in the empire. Name them.
Answer:
Bohemians, Slovaks, Slovens, Croats, and Roumans were peasant people that lived in the empire.

Question 11.
Why do you think conservatism needs to curb freedom to express one’s opinion and criticise?
Answer:

• Conservatism is the dominance of society by an aristocracy. It is incompatible with democracy, prosperity, and civilization in general.
• The conservatives did not tolerate criticism and dissent and sought to curb activities that questioned the legitimacy of autocratic governments.
• They imposed censorship laws to control the ideas of liberty and freedom associated with the French Revolution.

Question 12.
Read the following information and answer the questions given below.

Some important years
1797	Napoleon invades Italy; Napoleonic wars begin.
1814-1815	Fall of Napoleon; the Vienna Peace Settlement.
1821	Greek struggle for independence begins.
1848	Revolutions in Europe; artisans, industrial workers, and peasants revolt against economic hardships; middle classes demand constitution and representative governments; Italians, Germans, Magyars, Poles, Czechs, etc., demand nation-states.
1859-1870	Unification of Italy.
1866-1871	Unification of Germany.
1905	Slav nationalism gathers force in the Habsburg and Ottoman Empires.

a) What are the demand of middle classes? (SA-III : 2016-17)
Answer:
The demands of middle classes were

1. Constitution and
2. Representative government.

b) With the invasion on which country, did Napoleanic wars begin? (SA-III : 2016-17)
Answer:
Nepoleonic wars begin with invasion of Italy.

c) In which year was the Vienna peace conference held? (SA-I : 2018-19)
Answer:
Vienna Peace Conference was held in 1815 A.D.

d) Who was ruling France during the 1848 revolution? (SA-I : 2018-19)
Answer:
Louis Phillippe.

e) Who completed the unification of Italy? (SA-I : 2018-19)
Answer:
Victor Immanuel-ll, completed the Unification of Italy.

f) The Greek struggle for independence started in which year? (SA-I : 2018-19)
Answer:
1821 A.D.

g) When did Napoleon invade Italy?
Answer:
Napoleon invaded Italy in 1797 AD.

h) When was the Vienna Peace Settlement signed?
Answer:
The Vienna Peace Settlement was signed in 1815 A.D.

i) What were the two nations that united in the mid 19th centuries?
Answer:
Italy and Germany were the two nations that united in the mid 19th century.

j) Who revolted against economic hardship?
Answer:
Industrial workers and peasants revolted against economic hardship.

k) What were the demands of the middle class in 1848 revolt?
Answer:
The middle class demanded constitutions and representative governments.

Question 13.
Do you think our country has a liberal democratic political system? Give your reasons.
Answer:

• In India supreme power rests with the people.
• India is a republic country.
• Everyone is equal before law.
• Every citizen of 18 years and above has the right to vote.
• Any citizen is eligible to contest for any political office.

Hence we can say India has liberal democratic political system.

Question 14.
Point out the following on the Europe map.

1. Corsica
2. Sardinia
3. Poland
4. Germany
5. France

Question 15.
Locate the following on the Europe map.

1. Hungary
2. Serbia
3. London

Question 16.
What is the caricature? What does it represent?
Answer:

• A funny drawing of someone that makes them look silly or sometimes criticizes someone.
• It usually tells us about an incident or a person of that age.
• It symbolizes the wrong practices or criticizes that person on that grounds or informs us about the other side of that person.

These AP 10th Class Physical Science Chapter Wise Important Questions 10th Lesson Chemical Bonding will help students prepare well for the exams.

AP State Syllabus 10th Class Chemistry 10th Lesson Important Questions and Answers Chemical Bonding

10th Class Chemistry 10th Lesson Chemical Bonding 1 Mark Important Questions and Answers

Question 1.
What is a chemical bond? (AP March 2015)
Answer:
An attractive force between two atoms in a molecule is called a chemical bond.

Question 2.
Write the names of any two compounds which have ionic bond. (TS June 2016)
Answer:
1) NaCl
2) MgCl₂

Question 3.
Draw the structural diagram of Ammonia molecule as per the valence-shell electron pair repulsion theory. (TS March 2016)
Answer:

Question 4.
Show the formation of HC/ molecule with Lewis dot structures using the information given below. (TS March 2017)

Answer:

Question 5.
Explain, why bonding angle (HOH) in water is 104° 31′ instead of 109° 28′? (TS June 2018)
Answer:
Due to the repulsion between the lone pair of electrons and bond pair of electrons in water molecule the bond angle will be 104° 31′ rather than 109° 28′.

Question 6.
Imagine and write what type of ion can be formed generally by an atom of element with low ionisation energy, low electron affinity with high atomic size? (AP March 2019)
Answer:
Cation or positivity charged ion can be formed generally by an atom of element with low ionisation energy, low electron affinity with high atomic size.

Question 7.
Draw the structure of Methane molecule and mention bond angle. (TS March 2019)
Answer:
Structure of methane CH₄. Tetrahedral structure with bond angle 109°28′.

Bond Angle is 109°28′

Question 8.
Why do elements form chemical bonds? (TS SCERT: 2019-20)
Answer:

• Elements are unstable if they contain less than eight electrons (octet) in their valency shell.
• Hence, they form chemical bond with other elements to get octet in their valency shell.

Question 9.
How is covalent bond formed?
Answer:
A covalent bond is formed by the sharing of electrons between two atoms.
Ex : Bonding in H₂ molecule, O₂ molecule, N₂ molecule, etc.

Question 10.
What is ‘Octet rule’?
Answer:
Octet rule :
Presence of 8 electrons in the outermost shell of an atom or a molecule is called ‘octet rule’.

Question 11.
What is ‘Bond length’?
Answer:
Bond length :
It is the inner-nucleus distance between the two atoms in a molecule. It is measured in Angstrom, 1 Å = 10^-8 cm.

Question 12.
How is a cation formed?
Answer:
A cation is formed when an atom loses electrons.

Question 13.
How is an anion formed?
Answer:
An anion is formed when an atom gains electrons.

Question 14.
Which type of compounds are more soluble in polar solvents?
Answer:
Ionic compounds are more soluble in polar solvents.

Question 15.
Which compounds exhibit high melting and boiling points?
Answer:
Ionic compounds exhibit high melting and boiling points.

Question 16.
What is electronic configuration?
Answer:
A systematic arrangement of electrons in the atomic orbits is called electronic configuration.

Question 17.
Why are molecules more stable than atoms?
Answer:
Molecules have lower energy than that of the combined atoms. Molecules are more stable than atoms since chemical species with lower energy are more stable.

Question 18.
What is ionic linkage?
Answer:
When two oppositely charged ions are engaged in a bond, it is known as ionic linkage.

Question 19.
On which factors do anions depend?
Answer:

1. Atomic size
2. Ionisation potential
3. Electron affinity
4. Electronegativity

Question 20.
How do you know the valence of a metal?
Answer:
The number of electrons lost from a metal atom is the valence of its element which is equal to its group number.
Ex : Na and Mg have valence 1 and 2 respectively.

Question 21.
How do you know the valence of a non-metal?
Answer:
The number of electrons gained by a non-metal element for its atom is its valency, which is equal to 8 – its group number. Ex : The valency of chlorine is (8 – 7) = 1.

Question 22.
What is Tonic bond’?
Answer:
The electrostatic attractive force that keeps cation and anion together to form a new electrically neutral compounds is called ionic bond.

Question 23.
Why do atoms combine and form molecules?
Answer:
The energy of molecule is less than the total energy of constituent atoms. Therefore atoms combine and go to a stable state of lower energy.

Question 24.
What is ‘orbital concept of bond formation’?
Answer:
Atoms with half-filled or vacant orbitals try to get paired electrons in those orbitals by bond formation, i.e. by losing, gaining or sharing of electrons.

Question 25.
Name the bonds present in the molecules
i) BaCl₂
ii) C₂H₄.
Answer:
i) In BaCl₂ – Ionic.
ii) In C₂H₄ – Covalent (double bond H₂C = CH₂).

Question 26.
Why are ionic compounds good electrolytes?
Answer:

• Electrolytes produce ions in solution, which carry current.
• Ionic compounds in the fused state and aqueous solutions contain ions moving freely. Hence they conduct electricity.

Question 27.
When is ionic bond formed between atoms?
Answer:
Ionic bond is readily formed between atoms of elements with a low ionisation energy and atoms of elements with high electronegativity.

Question 28.
What is crystal lattice’?
Answer:
In a crystal of an ionic compound, each ion is surrounded by oppositely charged ions. The ions arrange themselves at an optimum distance with regular periodicity in a well-defined three-dimensional network called crystal lattice.

Question 29.
What is Lattice energy’?
Answer:
The energy released when gaseous positive and negative ions are brought together from infinity to form one mole ionic crystals is called lattice energy.

Question 30.
How is a σ (sigma) bond formed?
Answer:
By the axial or head on overlap of pure orbitals or hybrid orbitals of two atoms.

Question 31.
How is a π (pi) bond formed?
Answer:
By the lateral or parallel overlap of only pure atomic orbitals after the a bond formation.

Question 32.
Which type of atoms easily enter ionic bonding?
Answer:
An atom with low ionization potential and another with high electron affinity.

Question 33.
What is a polar bond?
Answer:
A covalent bond in a heteroatomic molecule.
Eg : HCl.

Question 34.
What is meant by inter-nuclear axis?
Answer:
The hypothetical line joining the centre of nuclei of two atoms in a molecule.

Question 35.
What are multiple bonds?
Answer:
Double and triple bonds are multiple bonds.

Question 36.
How many a and π bonds are in O₂ molecule?
Answer:
One σ and one π bond.

Question 37.
What are Lewis structures?
Answer:
The symbol of the atom gives the core (or kernel) of the atom, in which valence electrons are shown as dots (•), circles (O) or crosses (x). Thus in Na, Na represents the core of sodium atom and the cross (x) represents the valence electron of sodium.

Question 38.
What are the structures of sodium chloride and calcium chloride crystals?
Answer:
Sodium chloride has face centered cubic structure. Calcium chloride has body centered cubic structure.

Question 39.
NaCl dissolves in water but not in benzene. Explain.
Answer:
NaCl dissolves in water because of hydration. Water being a polar molecule has positive and negative ends which hydrate Na⁺ and Cl^– ions. Benzene being non-polar cannot solvate the ions of NaCl.

Question 40.
What are the bond angles in H₂O and NH₃ molecule?
Answer:
Bond angle in H₂O molecule is 104° 30′.
Bond angle in NH₃ molecule is 107°.

Question 41.
What are the forces present in an ionic bond?
Answer:
Electrostatic forces of attraction are present in ionic bonds.

Question 42.
Which forces are weaker forces and where are they operative?
Answer:

1. Van der Waal’s forces are very weak forces.
2. They are operative between non-polar molecules.

Question 43.
Which compounds exhibit low melting and boiling points?
Answer:
Covalent compounds exhibit low melting and boiling points when compared to ionic compounds.

Question 44.
How are cations formed?
Answer:
The metal atoms lose electrons to form positively charged ions or cations.

Question 45.
Why is a molecule of hydrogen more stable than the uncombined atoms?
Answer:
When a molecule of hydrogen is formed from the atoms, energy is released (104 Kcal/mol). Thus the molecules possessing lower energy are more stable than the atoms.

Question 46.
How many sigma and pi bonds are present in acetylene molecule between carbon atoms?
Answer:
\(\mathrm{HC} \equiv \mathrm{CH}\), one sigma and two pi bonds are present.

Question 49.
In case of ionic substances, a more appropriate term is formula weight, rather than ‘molecular weight’. Why?
Answer:
Molecules are not present in ionic substances. Only ions are present. The formula of an ionic substance represents the simpler ratio of ions in one mole of crystal. Hence a more appropriate term is ‘formula weight’.

Question 50.
Write a short note on bond angles.
Answer:
It is the average angle between two adjacent atoms bonded to the central atom in a molecule. Molecules with larger bond angles are more stable than those with smaller angles.

Question 51.
Sulphur dioxide is a diamagnetic molecule. Explain.
Answer:
Sulphur dioxide (SO₂) is a diamagnetic molecule because it has all electrons paired (no free electrons).

Question 52.
What is an ion?
Answer:
An ion is an electrically charged atom (or group of atoms).

Question 53.
What is a Coordination number?
Answer:
The number of ions of opposite charge that surround a given ion of given charge is known as coordination number of that given ion. –

Question 54.
What factors affect or which factors influence the formation cation or anion?
Answer:
Factors affecting formation of anion or cation are :

1. Atomic size,
2. Ionization potential,
3. Electron affinity,
4. Electronegativity.

Question 55.
Two elements X and Y have the following configurations.
X = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
Y = 1s² 2s² 2p⁶ 3s² 3p⁵
What is the formula of the compound?
Answer:
The electronic configuration of X is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².
So its valency is 2.
The electronic configuration of Y is 1s² 2s² 2p⁶ 3s² 3p⁵.
So its valency is 1.
∴ The formula of the compound is XY₂.

Question 56.
The electronegativities of two elements are 1 and 3. What type of bond is formed between the two elements? Why?
Answer:
The electronegativity difference of elements = 3 – 1 = 2.
So the electronegativity difference is more than 1.9. Therefore the bond formed between the elements is ionic in nature.

Question 57.
What do you mean by Doublet configuration?
Answer:
If two electrons are present in valence shell, then it is called doublet configuration.
Eg.: Helium exhibits doublet configuration.

Question 58.
Write Lewis symbol of potassium and calcium.
Answer:
Potassium – \(\dot{\mathrm{K}}\) and Calcium – •Ca•

Question 59.
Which of the following is / are true?
1) Ionic compounds exist as solids.
2) Ionic compounds have high melting and boiling points.
3) Ionic compounds conduct electricity in solid state.
4) Ionic compounds have low melting and boiling points.
Answer:
Ionic compounds generally exists as solids and they have very high melting and boiling points and they conduct electricity in aqueous or molten state.
So first and second statements are true.

Question 60.
How many a and n bonds are there in acetylene molecule?
Answer:
The structure of acetylene is given by
\(\mathrm{H}-\mathrm{C} \equiv-\mathrm{H}\)
So they are 3a and 2n bonds.

Question 61.
What is the valency of carbon in CO₂?
Answer:
The valency of oxygen is 2. So the valency of carbon = 2 × 2 = 4.

Question 62.
Which of the following does not get Helium configuration during formation of chemical bonding?
1) Hydrogen,
2) Lithium,
3) Beryllium,
4) Oxygen.
Answer:
Oxygen attains Neon configuration when it undergoes chemical bondings and the rest will attain Helium configuration.

Question 63.
Write the valencies of following elements.
a) Be
b) N and what is the compound formed when these two reacted?
Answer:
a) The electronic configuration of Be is 1s² 2s². So its valency is 2.
b) The electronic configuration of Nitrogen is 1s² 2s² 2p³. So its valency is 3.
∴ Formula of the compound is Be₃N₂.

Question 64.
Which of the following solutions are conductors of electricity?
a) Sugar solution,
b) Alcohol solution,
c) Glucose solution,
d) Salt solution.
Answer:
Salt solution is good conductor of electricity because common salt (NaCl) is an ionic compound and the rest are covalent compounds.

Question 65.
Why are noble gases (inert gases) stable?
Answer:

1. Noble gases are stable because their outermost orbit contains 8 or 2 electrons.
2. Noble gases exist an individual atoms.

10th Class Chemistry 10th Lesson Chemical Bonding 2 Marks Important Questions and Answers

Question 1.
Represent each of the following molecules using Lewis notation. (TS March 2015)
(i) Calcium and Chlorine to form Calcium chloride.
(ii) Formation of Oxygen molecule from Oxygen atoms.
Answer:

Question 2.
Between a neutral atom and its cations which has bigger size? Why? (TS June 2016)
Answer:

• A neutral atom has bigger in size than its cation.
• A cation has more protons and nucleus of the cation attracts the electrons in the outermost orbital more.
• Hence, the radius of the anion decreases. It means size of the anion decreases.
• So, a neutral atom is bigger than its cation.

Question 3.
Draw the diagram to show the formation of Oxygen molecule by Valence bond theory. (TS March 2017)
Answer:

Question 4.
Explain Ionic bond with suitable example. (TS June 2018)
Answer:
1) Sodium (Na) looses one electron and forms Sodium ion (Na⁺).
Na → Na⁺ + 1e^–

2) Chlorine (Cl) gains one electron and forms chloride ion (Cl^–).
Cl + 1e^– → Cl^–

3) Positive sodium ion (Na+) and negative chloride (Ct) ion come together due to electrostatic forces, participates in ionic bond and form NaCl.
Na⁺ + Cl^– → NaCl

Question 5.
Give two examples of each to ionic and covalent compounds. (AP SCERT: 2019-20)
Answer:
1) Ionic compounds eg : NaCl, MgCl₂
2) Covalent compounds eg : Cl₂, HCl

Question 6.
Distinguish between a sigma and a pi bond.
Answer:

Sigma bond	Pi bond
1. It is formed by the end-end on overlap of orbitals.	1. It is formed by the lateral overlap of orbitals.
2. It has independent existence.	2. It has no independent existence.
3. It is a strong bond. Because axial overlap is more.	3. It is a weak bond. Because lateral overlap is less.
4. There can be only one a bond.	4. There can be one or two 7t bonds between two atoms.
5. All orbitals form ‘o’ bond.	5. Only p, d orbitals form a bond.

Question 7.
Write about ‘Hydrogen bond’
Answer:

• Hydrogen bond is formed between molecules in which hydrogen atom is attached to an atom of an element with large electronegativity and very small size (F, O, N). Because in hydrogen bond the molecules associate themselves and hence possess higher B.P’s and M.P’s.
• The hydrogen bond formed between two molecules is called inter-molecular hydrogen bond.
• The hydrogen bond formed between different groups of the same molecule is called intra-molecular hydrogen bond.

Question 8.
Bring out the difference between ionic and covalent bonds.
Answer:

Ionic bond	Covalent bond
1. It is formed by transference of electrons from one atom to the other.	1. It is formed by the sharing of electron pairs by two atoms.
2. Electrostatic.	2. Not electrostatic, but rigid.
3. Ionic substances are formed by ionic bonds.	3. Molecules are formed by covalent bonds.
4. Non-directional.	4. Directional.

Question 9.
What is hybridisation?
Answer:
In the formation of molecules, the atomic orbitals of the atoms may hybridise.

1. It is the process of mixing up of atomic orbitals of an atom to form identical hybrid orbitals.
2. This takes place only during the formation of bond.
3. There should not be much difference in the energies of the orbitals that hybridise.
4. The number of hybrid orbitals formed is equal to the number of hybridising atomic orbitals.
5. Hybrid orbitals form a bonds only not n bonds.

Question 10.
What is ionisation? Give one example.
Answer:
1) The process of removal of electron (s) from an atom or molecule is termed as ionisation.
Eg : Na → Na⁺ + e^–

2) Dissociation of an ionic solid into constituent ions upon its dissolution in a suitable solvent, is also called ionisation.
Eg : NaCl_(aq) → Na⁺_(aq) + Cl^–_(aq)

Question 11.
Write a short note on octet rule with example.
Answer:
Atoms try to get 8 electrons in their outermost shell (inert gas structure) by combining with other atoms. In order to get 8 outer electrons, atoms may lose to, gain from or share electrons with other atoms.

Question 12.
What are the important characteristic features of hybridisation?
Answer:

• Orbitals on a single atom only would undergo hybridization.
• The orbitals involved in hybridisation should not differ largely in their energies.
• The number of hybrid orbitals formed is equal to the number of hybridising orbitals.
• The hybrid orbitals form stronger directional bonds than the pure s, p, d atomic orbitals.
• It is the orbitals that undergo hybridisation and not the electrons.
• Concept of hybridisation is useful in explaining the shape of molecules.

Question 13.
Why is a large amount of energy needed to remove an electron from a neutral gaseous neon atom than the energy needed to remove an electron from gaseous sodium atom?
Answer:
Na (g) +118.4 K.cal → Na⁺ + e^–
Ne (g) + 497.0 K.cal → Ne⁺ + e^–

Orbitals which are fully-filled are very stable, so need large amount of energy to remove an electron from them.

Question 14.
What are the drawbacks of electronic theory of valence?
Answer:
1) When covalent bond formed between any two atoms, irrespective of the nature of the atoms, the bond lengths and bond energies’ are expected to be same. But practically it was observed that bond lengths and bond energies are not same when the atoms that form the bond are different.

2) This theory fails to explain the shapes of molecules.

Question 15.
What is the structure of NaCl and write its coordination number of its constituent ions?
Answer:
The structure of NaCl is face centred cubic lattice.
Its coordination number is 6 for Na⁺ and Cl_–.

Question 16.
Why is there absorption of energy in certain chemical reactions and release of energy in other reactions?
Answer:
If bond dissociation energy of reactants is more than bond energy of products, then energy is absorbed in the chemical reaction.

If bond dissociation energy of reactants is less than bond energy of products, then energy is released in the chemical reaction.

Question 17.
Why do ionic compounds dissolve in polar solution and covalent compounds dissolve in non-polar solution?
Answer:
Ionic compounds are polar in nature so they are soluble in polar solvents whereas covalent compounds are non-polar in nature so they are soluble in non-polar solvents.

Question 18.
Identify the following whether they are either oxidation or reduction reactions.

Answer:
i) Oxygen atom is gaining electrons. So it is reduction reaction.
ii) Potassium atom is losing electron. So it is oxidation reaction.
iii) Ferric ion is gaining electron. So it is reduction reaction.

Question 19.
Elements A, B, and C have atomic numbers 9, 20, and 10 respectively.
a) State which one is (i) a metal, (ii) a non-metal, (iii) chemically inert.
b) Write down the formula of the compound formed by two of the above elements.
Answer:
a) i) Element with atomic number 20 is a metal because its electronic configuration is 2, 8, 8, 2. It belongs to 2^nd group and the element is calcium.
ii) Element with atomic number 9 is a non-metal because its electronic configuration is 2, 7. So it belongs to 17^th group and it is Fluorine.
iii) Element with atomic number 10 is inert gas because its electronic configuration is 2, 8 and the element is Neon.

b) The formula of compound formed between elements Calcium and Fluorine is CaF₂.

Question 20.
In the formation of the compound XY₂, an atom X gives one electron to each Y atom. What is the nature of bond in XY₂? Give two properties of XY₂.
Answer:
Two electrons are transferred from X to Y. X forms positive ion and Y forms a negative ion. So the bond formed is ionic in nature.
Properties of ionic compounds :
a) They are hard crystals.
b) They have high boiling point and melting point.
c) They are soluble in water.

Question 21.
Element X is a metal with valency 2. Element Y is a non-metal with valency 3.
i) Write equations to show X and Y form ions.
Answer:
X is a metal with valency 2.

ii) If Y is a di-atomic gas, write the equation for the direct combination of X and Y to form a compound.
Answer:
4X + 3Y₂ → 2X₂Y₃

Question 22.
What are the differences between sodium atom and sodium ion?
Answer:

• Sodium atom is neutral whereas sodium ion has unipositive charge.
• The size of sodium ion is smaller than sodium atom.
• The properties of sodium ion is different when compared with sodium.

Question 23.
What is the percent of p-character in sp, sp² and sp³ hybrid orbitals?
Answer:
In sp the p-character is 50%.
In sp² the p-character is 66.66%.
In sp³ the p-character is 75%.

Question 24.
What is the percent of s-character in sp, sp² and sp³ hybrid orbitals?
Answer:
In sp hybrid orbitals s-character is 50%.
In sp² hybrid orbitals s-character is 33.33%.
In sp³ hybrid orbitals s-character is 25%.

Question 25.
A chemical compound has following Lewis notation.

a) How many valence electrons does element Y have?
b) What is the valency of element Y?
c) What is the valency of element X?
d) How many covalent bonds are there in the molecule?
e) Suggest a name for the element X and Y.
Answer:
a) The valence electrons in Y are 5.
b) The valency of Y is 3.
c) The valency of X is 1.
d) There are three covalent bonds.
e) The element Y is Nitrogen and X is Hydrogen.

Question 26.
The electronic configurations of three elements.
X is 2, 6; Y is 2, 8, 7; Z is 2, 8,1.
In each ease given below state whether the bonding is ionic or covalent and give the formula of molecules of the compound formed,
a) Between two atoms of X.
Answer:
As we move from left to right in a period non-metallic character increases. So Z is a metal and remaining two are non-metals.
Therefore between two atoms of X, there would be covalent bond. The formula of compound is X₂.

b) Between the atom X and atom Z.
Answer:
X is a non-metal and Z is a metal. So between these two atoms, there would be an ionic bond.
The valency of X is 2 and the valency of Z is 1.
So the formula of compound is Z₂X.

c) Between the atom Y and atom Z.
Answer:
Y is also non-metal and we know Z is metal.
The valency of Y is 1.
So the compound formed is ZY.

Question 27.
Electronic configuration of X is 2, 8, 1 and electronic configuration of Y is 2, 8, 7. Explain what type of bond is formed between them.
Answer:
The element with electronic configuration 2, 8,1 is sodium which is a metal. Similarly the element with electronic configuration 2, 8, 7 is chlorine which is a non-metal. The electronegativity difference between these two elements is more than 1.9 so they form ionic bond.

Question 28.
Complete the following statements.
i) The bond which is formed by transfer of an electron from one atom A to another atom B is called ……………
Answer:
Ionic bond

ii) The atoms A and B become ions. Thus A – 2e^– = …………….. and B + e^– = ………….
Answer:

iii) The formula of the compound is
Answer:
The valency of A is 2 and valency of B is 1. So the compound formed is AB₂.

Question 29.
Answer the following.
i) What is the valency of Nitrogen in Ammonia?
Answer:
The formula of Ammonia is NH₃. We know valency of hydrogen is 1. So valency of Nitrogen is 3.

ii) What is the valency of Oxygen in Water?
Answer:
The formula of water is H₂O. The valency of hydrogen is 1. So the valency of oxygen is 2.

iii) What is the valency of Carbon in Carbon tetra chloride?
Answer:
The formula of carbon tetra chloride is CCl₄. The valency of chlorine is 1. So the valency of carbon is 4.

10th Class Chemistry 10th Lesson Chemical Bonding 4 Marks Important Questions and Answers

Question 1.
What is Hybridisation? Explain the formation of BeF, molecule using hybridisation. (AP June 2017)
Answer:
Hybridisation :
Hybridisation is a phenomenon of intermixing of atomic orbitals of almost equal energy which are present in the outer shells of the atom and their reshuffling or redistribution into the same number of orbitals but with equal properties like energy and shape.

Formation of BeF₂ molecule :

1. ₄Be has electronic configuration 1s² 2s².
2. In excited state electronic configuration of ₄Be is 1s² 2s¹ 2p_x¹
3. ₄Be allows its 2s orbitals and 2p_x orbitals which contain unpaired electrons to intermix and redistribute to two identical orbitals.
4. The hybridisation is called ‘sp’ hybridisation and form two ‘sp’ hybrid orbitals. Each orbital contains one electron.
5. ₉F has electronic configuration 1s² 2s² 2p⁵ (or) 1s² 2s² 2px² 2py² 2pz¹
6. F contains one unpaired electron.
7. Two Fluorine atoms come closure to Be and form two covalent bonds.
   σsp – p and σsp – p
8. Now the BeF₂ has (F \(\widehat{\mathrm{Be}}\) F) angle of 180°.
   

Question 2.
The arrangement of electrons in different shells of atoms of 18th Group elements is given in the table.

Answer the following : (AP March 2017)
(i) What is the general electronic configuration of the above elements except He?
(ii) What is the valency of Argon?
(iii) Write Lewis dot structure of Neon.
(iv) Why the above elements do not take part in bond formation?
Answer:
(i) ns² np⁶
(ii) Zero
(iii)

(iv) They are stable as they have 8 electrons (except Helium) in their outer most orbit.

Question 3.
“Nitrogen and Hydrogen react to form a molecule of Ammonia (NH₃). Carbon and Hydrogen react to form a molecule of Methane (CH₄).”
For each reaction :
a) What is the valency of each of the atom involved in the reaction?
b) Draw the dot structure of the products that are formed. (AP June 2018)
Answer:
a) In ammonia : Nitrogen valency – 3, Hydrogen valency – 1
In methane : Carbon valency – 4, Hydrogen valency – 1

b)

Question 4.
Explain the formation of Boron tri-fluoride molecule by Hybridization. (TS June 2018)
Answer:
1) Electron configuration of Boran at ground state.

2) Electron configuration of Boran at excited state is

3) As it forms three identical B-F bonds in BF₃.
4) In excited state of Boran, one ‘s’ orbital and two ‘p’ orbitals undergoes hybridization and forms three sp² orbitals.
1s + 2p → 3sp²
5) Three sp² orbitals make end – on – end overlap with three ‘p’ orbitals of fluorine atoms.
6) They form three sp² – p sigma bonds.
7) In this way Boran tri-fluoride molecule is formed.
8)

Question 5.
Explain the formation of BF₃ molecule with the help of Valence Bond theory? (TS March 2018)
Answer:
Formation of BF₃ molecule :

1. ₅B has electronic configuration 1s² 2s² 2p_x.
2. The excited electronic configuration of ₅B is 1s² 2s¹ 2p_x¹ 2p_y¹.
3. As it forms three identical B-F bonds in BF₃
4. It is suggested that excited ‘B’ atom undergoes hybridisation.
5. There is an intermixing of 2s, 2p_x, 2p_y orbitals and their redistribution into three identical orbitals called sp² hybrid orbitals.
6. For three sp² orbitals to get separated to have minimum repulsion the angle between any two orbitals is 120° at the central atom and each sp² orbital gets one electron.
7. Now three fluorine atoms overlap their 2p_z orbitals containing unpaired electrons (F₉ 1s² 2s² 2p_x² 2p_y² 2p_z²) the three sp² orbitals of ‘B’ that contain unpaired electrons to form three ssp²-p bonds.

Question 6.
Explain the formation of N₂ molecule using Valence Bond theory. (TS June 2019)
Answer:
Formation of N, molecule (Valence Bond theory) :

1. ₇N has electronic configuration 1s² 2s² 2p_x¹ 2p_y¹ 2p_z.
2. Suppose that p_x orbital of one ‘N’ atom overlaps the ‘p_x‘ orbital of the other ‘N’ atom giving σ p_x – p_x bond along the inter – nuclear axis.
3. The p_y and p_z orbitals of one ‘N’ atom overlap the p_y and p_z orbital of other ‘N’ atom laterally, respectively perpendicular to inter – nuclear axis giving π p_y – p_y and π p_z-p_z bonds.
4. Therefore, N₂ molecule has a triple bond between two nitrogen atoms.

Question 7.
If the electronic configurations of atoms A and B are 1s², 2s², 2p₆, 3s², 3p¹ and 1s², 2s², 2p₄ respectively, then
a) which atom forms negative ion?
Answer:
Given electronic configuration of atom A is 1s² 2s² 2p⁶ 3s² 3p¹, i.e. Aluminium and B is 1s² 2s² 2p⁴, i.e. Oxygen.

The atom ‘B’ tends to form negative ion by gaining two electrons in order to get nearest inert gas. Neon’s configuration is 1s² 2s² 2p⁶. So its valency is 2.

b) which atom forms positive ion?
Answer:
The atom ‘A’ tends to form positive ion by losing three electrons in order to get nearest inert gas. Neon’s configuration is 1s² 2s² 2p⁶.

c) what is the valency of atom A?
Answer:
Valency of atom ‘A’ is ‘3’.

d) what is the molecular formula of the compound formed by atoms A and B ?
Answer:
According to Criss-Cross method, the molecular formula of the compound formed by atoms both A and B is A₂B₃, i.e. Al₂O₃.

Question 8.
Writs the salient features of VSEPRT.
(OR)
Explain VSEPR theory.
Answer:
The full form of VSEPRT is Valence Shell Electron Pair Repulsion Theory.

1. VSEPRT considers electrons in the valence shells which are in covalent bonds and in lone pairs as charge clouds that repel one another and stay as far apart as possible which will give specific shapes to molecules.
2. The presence of lone pair in the central atom causes slight distortion of bond angles from expected regular shape.
3. If the angle between lone pair and bond pair increases at the central atom due to more repulsion, the actual bond angles between atoms must be decreased.
4. If two bond pairs are present without any lone pair, the shape of the molecule is linear with bond angle 180°.
5. If three bond pairs are present without any lone pair, the shape of the molecule is trigonal planar with bond angle 120°.
6. If there are four bond pairs in the valency shell of central atom without lone pair, the shape is tetrahedron and the bond angle is 109°28′.
7. If there are three bond pairs and one lone pair, the shape of the molecule is pyramidal.
8. If there are two bond pairs and two lone pairs, the shape is V.

Question 9.
Do you think that a pair of Na⁺Cl^– as units would be present in the solid crystal? Explain.
Answer:

• No, the electrostatic forces are non-directional.
• Therefore, it is not possible for one Na⁺ to be attracted by one Cl^– and vice-versa.
• Depending upon the size and charge of particular ion, number of oppositely charged ions get attracted by it, but, in a definite number.
• In sodium chloride crystal each Na⁺ is surrounded by 6 Cl^– and each Cl^– by six Na⁺ ions.
• Ionic compounds in the crystalline state consists of orderly arranged cations and anions held together by electrostatic forces of attractions in three dimensions.

Question 10.
Explain the valence bond theory.
Answer:
Valence bond theory :

1. A covalent bond between two atoms is formed when the two atoms approach each other closely and one atom overlaps its valence orbital containing unpaired electron with the valence orbital of other atom that contains the unpaired electron of opposite spin.
2. The greater the overlapping of the orbitals, the stronger will be bond.
3. Valence bond theory gives a directional character to the bond when other than ‘s’ orbitals are involved.
4. Electron pair in the overlapping orbitals is shared bv both the atoms involved in the overlapping.
5. If orbitals overlap along inter-nucleus axis, they form a strong bond called sigma (σ) bond.
6. If the orbitals overlap laterally, they form a weak bond called pi (π) bond.

Question 11.
Answer the following.
a) Name the charged particles which attract one another to form ionic or electro-valent compounds.
Answer:
The charged particles are ions which are formed due to transfer of electrons from atom of one element to atom of other element.

b) In the formation of ionic compounds, electrons are transferred from one element to another. How are electrons involved in the formation of covalent compounds?
Answer:
In the formation of covalent bond electrons are mutually shared between atoms of elements.

c) The electronic configuration of Nitrogen is 2, 5. How many electrons in the outer- shell of a nitrogen atom are not involved in the formation of Nitrogen molecule?
Answer:
In the formation of Nitrogen molecules three pairs of electrons are mutually shared by the two nitrogen atoms. So each Nitrogen has two electrons which do not take part in bonding. Those two electrons are called lone pair.

d) In the formation of magnesium chloride, name the substance that is oxidized and the substance that is reduced.
Answer:
Two electrons are transferred from Magnesium atom to Chlorine atom in the formation of Magnesium chloride.

So Magnesium is oxidised (loss of electrons is oxidation) and Chlorine is reduced (gain of electrons is reduction).

Question 12.
The symbols of two elements with their atomic numbers are given below. ₁₆A and ₂₀B
i) Which element will form a cation?
Answer:
The atomic number of B is 20. So its electronic configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² or 2, 8, 8, 2. So it easily loses two electrons to form cation thereby attain inert gas stability.

ii) Which element will form an anion?
Answer:
The atomic number of A is 16. So its electronic configuration is 1s² 2s² 2p⁶ 3s² 3p⁴ or 2, 8, 6. So it easily gains two electrons to form anion. Therefore it attains inert gas stability.

iii) Show how each element forms an ion.
Answer:

iv) Which element will be oxidised in forming the ion?
Answer:
B is losing electrons. So it is oxidised. .

v) When the elements react, what will be the nature of the bond formed?
Answer:
When the elements react they form ionic bond because B is metal and A is non-metal.

Question 13.
Give one example for each of the following.
i) A polar covalent bond formed from two dissimilar atoms one of which is oxygen.
Answer:
In the formation water molecule, polar covalent bond is formed between two dissimilar atoms hydrogen and oxygen.

ii) A non-polar covalent compound formed from two similar atoms.

Answer:
The examples for a non-polar covalent compound formed from two similar atoms are Fluorine (F₂), Chlorine (Cl₂).

iii) A solid non-polar covalent compound.
Answer:
The example for solid non-polar covalent compound is Iodine (I₂).

iv) A polar covalent compound containing three shared pairs of electrons.

Answer:
The polar covalent compound containing three shared pairs of electrons is Ammonia.

Question 14.
The list of some substances is given below.
HCl, H₂O, Cl₂, NaBr, CH₄, NH₃, N₂, O₂, CaO, HF, I₂ and Br₂.
From the list above choose the substance / substances.

i) Which have only ionic bond in the molecules?
Answer:
NaBr, CaO have only ionic bond in the molecules,

ii) Which has a triple covalent bond in its molecule?
Answer:
N₂ has a triple covalent bond in its molecule (\(\mathbf{N} \equiv \mathbf{N}\)).

iii) Which are solids?
Answer:
Generally ionic compounds are solids. So NaBr, CaO are solids. I₂ being a covalent compound still it is solid.

iv) Which has a double covalent bond in its molecule?
Answer:
O₂ has a double covalent bond in its molecule (O = O).

v) Which is non-polar covalent liquid?
Answer:
The non-polar covalent liquid is Br₂.

Question 15.
There are elements with atomic numbers 4, 14, 8, 15 and 19. From this information answer the following questions.
a) A solid non-metal of valency 3.
Answer:
The element with atomic number 15 is phosphorus. Its electronic configuration is 2, 8, 5. So its valency is 3 and it is a solid non-metal.

b) A gas of valency 2.
Answer:
The element with atomic number 8 is oxygen. Its electronic configuration is 2, 6. So its valency is 2 and it is a gas.

c) A metal of valency 1.
Answer:
The element with atomic number 19 is potassium. Its electronic configuration is 2, 8, 8, 1. So its valency is 1 and it is a metal.

d) A non metal of valency 4.
Answer:
The element with atomic number 14 is silicon. Its electronic configuration is 2, 8, 4. Its valency is 4 and it is a non-metal.

Question 16.
Explain the following.
a) Ionic compounds conduct electricity.
Answer:
Ionic compounds can be electrolysed to give their constituent ions. The ions obtained by dissociation move freely in solution and hence conduct electricity. When ionic compound is dissolved in water or melted, it becomes a good conductor of electricity.

b) Ionic compounds have high melting and boiling points while covalent compounds have low melting and boiling points.
Answer:
The forces existing between ionic compounds are electrostatic in nature. They are strong forces. So in order to break these forces lot of energy is required. Therefore ionic compounds have higher boiling and melting points.

c) Ionic compounds dissolve in water whereas covalent compounds do not.
Answer:
Ionic compounds are polar in nature. So they are soluble in polar solvent like water whereas covalent compounds are non-polar in nature. So they are insoluble in water.

d) Ionic compounds are usually hard crystals.
Answer:
Due to strong attractive forces they are usually hard crystals.

Question 17.
If A, B, C and D are elements given that B is an inert gas (not Helium).

Element	Atomic Number
A	Z- 1
B	Z
C	Z + 1
D	Z + 4

What type of bonding would take place between (i) A and C and (ii) D and A and write their formulae?
Answer:
1) Given that B is inert gas.
So the valency of A is 1 and it is a non-metal and valency of C is 1 and it is metal and valency of D is 4 and it is a non-metal.

2) The bond formed between C and A is ionic nature and its formula is CA.
The bond formed between D and A is covalent nature and its formula is DA₄.

Question 18.
State whether the following statements are true or false. If statement is false, correct it.
i) In polar compounds the electropositive atom attracts the electron pair towards it.
Answer:
This statement is wrong. In polar compounds the more electronegative atom attracts the electron pair towards it which is known as electronegativity.

ii) Hydrogen chloride gas is a di-polar molecule.
Answer:
Chlorine is more electronegative than Hydrogen. So the electron pair shifts more towards chlorine atom. Thus partial positive charge is formed on Hydrogen and partial negative charge is formed on Chlorine. So it is dipolar molecule. So the statement is true.

iii) Covalent compounds are generally gases due to presence of weak electrostatic forces of attraction.
Answer:
This statement is false. The forces are not electrostatic and also they are weak.

iv) Atoms achieve stable electronic configuration only by transfer of electrons from one atom to another.
Answer:
This statement is false because they can acquire by not only electron transfer but also mutually sharing of electrons.

v) Ionic compounds are soft, solids or liquids at ordinary temperature.
Answer:
This statement is false because ionic compounds are generally hard solids.

Question 19.
Five atoms are labelled from A to E.

Atoms	Atomic Number	Mass Number
A	20	40
B	9	19
C	3	7
D	8	16
E	7	14

a) Which one of these atoms (i) contain 7 protons, (ii) has an electronic configuration 2, 7?
Answer:’
i) The atom E contains 7 protons because its atomic number is 7.
ii) The atom with electronic configuration 2, 7 is B because its atomic number is 9.

b) Write down the formula of the compound formed between C and D.
Answer:
The electronic configuration of C is 2, 1 since its atomic number is 3. The electronic configuration of D is 2, 6 since its atomic number is 8.
So the valency of C is 1. –
The valency of D is 2 (8 – 6 = 2).
∴ The compound formed between C and D is C₂ D.

c) Predict which are (i) metals, (ii) non-metals?
Answer:
Metals are A, C.
Non-metals are B, D, E.

Question 20.
Can you suggest an experiment to prove that ionic compounds possess strong bonds when compared to that of covalent bonds? Explain the procedure.
Answer:

• Take a small amount of sodium chloride (NaCl) on a metal spatula (having an insulated handle).
• Heat it directly over the flame of a burner.
• We will see that sodium chloride (NaCl) does not melt easily.
• Sodium chloride melts (and becomes a liquid) only on strong heating.
• This shows that sodium chloride which is an ionic compound possesses strong bonds.
• So it has a high melting point.
• Whereas covalent compound like naphthalene and carbon tetra chloride has low boiling points such as 80° C and 77° C respectively.
• The force of attraction between the molecules of a covalent compound is very weak.
• Only a small amount of heat energy is required to break these weak molecular forces, due to which covalent compound has low melting points and low boiling points.

Question 21.
The electronic configurations of following elements are given below.

From these values complete the table.

Compound	Type of bonding
Lithium chloride
Lithium hydride
Hydrogen chloride
Carbon tetrachloride

Answer:
a) Lithium is metal and chlorine is non-metal. So the bond is ionic in nature.
b) Lithium is metal and hydrogen is non-metal. So the bond is ionic in nature.
c) Hydrogen and chlorine are two dissimilar non-metals. So the bond formed is polar covalent bond.
d) Carbon and chlorine are dissimilar non-metals but electronegativity difference is less. So they form non-polar covalent bond.

Compound	Type of bonding
Lithium chloride	Ionic bond
Lithium hydride	Ionic bond
Hydrogen chloride	Polar covalent bond
Carbon tetrachloride	Non-polar covalent bond

Question 22.
Draw the structure of O₂ by using valence bond theory.
Answer:
O₂ Formation :

Question 23.
Draw the structure of N₂.
Answer:

Question 24.
Draw the structure of molecules by Lewis method.
Answer:
Formation of F₂:

Formation of O₂ :

Formation of N₂ :

Formation of CH₄ :

Formation of NH₃ :

Formation of H₂O :

Formation of BeCl₂ :

Formation of BF₃ :

Question 24.
Explain the formation of the following molecules using Lewis theory.
a) N₂
b) O₂
(OR)
Write the formation of double bond and triple bond according to Lewis theory.
Answer:
a) Formation of N₂ molecule by Lewis theory :

1. The electronic configuration of ’N’ atom is 2, 5 and to have octet in the valence shell it requires three more electrons.
2. When two nitrogen atoms approach each other, each atom contributes 3 electrons for bonding.
3. There are six electrons shared between two nitrogen atoms in the form of three pairs.
4. Therefore, there is a triple bond between two nitrogen atoms in N₂ molecule.

b) Formation of O₂ molecule by Lewis theory :

1. The electronic configuration of ₈O is 2, 6.
2. Oxygen atom has six electrons in its valence shell.
3. It requires two more electrons to get octet in its valence shell.
4. Therefore oxygen atoms come close and each oxygen atom contributes two electrons for bonding.
5. Thus, there exist two covalent bonds between two oxygen atoms in O₂ molecule as there are two pairs of electrons shared between them.
6. Two pairs of electrons are distributed between two oxygen atoms.
7. So, we can say that a double bond is formed between two oxygen atoms in O₂ molecule.
8. By viewing the following diagram, both the oxygen atoms have octet in the valence shell.

These AP 9th Class Social Studies Important Questions 4th Lesson Atmosphere will help students prepare well for the exams.

AP State Syllabus 9th Class Social 4th Lesson Important Questions and Answers Atmosphere

9th Class Social 3rd Lesson Hydrosphere 1 Mark Important Questions and Answers

Question 1.
Why does our skin dry up more during the winter? (SA-II : 2018-19)
Answer:
If the humidity is low in our atmosphere, our skin becomes dry during winter. This also leads to chapped lips.

Question 2.
Define relative humidity. (SA-I : 2019-20)
Answer:
Relative humidity: Relative humidity is the ratio between two things.

1. The maximum water vapour that the air can hold at a given temperature and pressure and
2. The actual amount of water vapour it holds at any given time.

9th Class Social 4th Lesson Atmosphere 4 Marks Important Questions and Answers

Question 1.
How many types of rainfall classified based on the origin of rainfall? What are they? Explain one of them? (SA-II : 2016-17)
Answer:
On the basis of origin, rainfall may be classified into three main types.

1. Convectional Rainfall
2. Orographic Rainfall
3. Cyclonic Rainfall.

Convectional Rainfall :
This type of rainfall occurs when moist air over the heated ground becomes warmer than the surrounding air and is forced to rise, expand, cool and yield some of its moisture.

It is common in low latitudes and on summer days in interior part of the continents, and usually come in the form of short heavy showers just after the hottest part of the day, some times accompanied by thunder and lightning.

Question 2.
Observe the information given below and write four sentences on ‘Pressure Beits and Planetary Winds’. (SA-III : 2016-17)

Answer:
According to the given picture :

• The Equatorial Low Pressure Belts : This low pressure belt extends from 0 to 5° North and South of the Equator.
• Sub – Tropical Pressure Beits : At about 30° North and South of the equator lies the area where the ascending equatorial air currents descends.
• Sub-polar Low Pressure belts : These belts are located between 60° and 70° in both the hemispheres and are known as sub-polar low pressure belts.
• Polar High Pressure belts ; At the North and South between 70° and 90° temperatures are always extremely low. These areas of polar high pressure are known as polar highs.

Planetary winds : Planetary winds are distributed all over the globe and blow in the same direction throughout the year. These winds originate due to the presence of permanent high pressure and low pressure belts on the surface of the earth. The main types of planetary winds are the trade winds, the westerlies and the polar winds.

Question 3.
Study the table and answer the questions given below. (SA-I : 2018-19)

Name of the sphere	Area	Characteristics In equator region
Troposphere	Upto 13 kms.	The entire weather phenomenon happens in this sphere. The temperature in the layer decreases as we go higher.
Stratosphere	Upto 50 kms.	This layer is almost free from clouds and associated weather phenomenon, making conditions most ideal for flying Jet air crafts. One important feature of stratosphere is that contains Ozone layer. The temperature increases with the increase in altitude.
Mesosphere	Upto 80 kms.	Meteorites burn up in this layer on entering from the space. Temperature starts decreasing with the increase in altitude.
Thermosphere	Up to 400 kms.	In thermosphere temperature rises rapidly with increasing height. It contains electrically charged particals known as ions. Radio rays transmitted from the earth by these ions.
Exosphere	Above 400 kms.	It is uppermost layer of the atmosphere. This is the highest layer and very little known about it.

1. Why do jet aircrafts fly in the stratosphere?
2. Which is the top most layer?
3. Which layer contains ions?
4. In which layer does precipitation and cyclones occur?
Answer:

1. Stratosphere layer is almost free from clouds and associated weather phenomenon, making conditions most ideal for flying jet aircrafts.
2. Exosphere. It is above 400 kms. It is uppermost layer of the atmosphere.
3. Thermosphere contains electrically charged particles known as ions.
4. Troposphere.

Question 4.
What are the effects of climate change on the contemporary World? (SA-I : 2018-19)
Answer:
The affect of climate change on contemporary world.
→ an increase in hunger and water crises.
→ health risks through rising air temperatures and heat waves.
→ increasing spread of pests and pathogens
→ loss of biodiversity.
→ melting of the polar caps.
→ El Nino and La-Nino effect.
→ Frequently cyclonic effect on coastal areas, etc.

9th Class Social 4th Lesson Atmosphere Important Questions and Answers

Question 1.
What is Coriolis effect?
Answer:
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.

Question 2.
About which layer do we have very little knowledge?
Answer:
Exosphere is the upper most layer of the atmosphere. This is the highest layer. Very little is known about it.

Question 3.
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 4.
Name and explain the classification of winds.
Depending upon the wind speed, their features, their directions, the way they occur, winds are classified into three types.
A) Planetary winds –
present on the planet as a whole through out the year, that blow continuously and regularly.

B) Seasonal winds –
Restricted to regions or seasonal in character like monsoons.

C) Local winds –
These blow due to local variation in the temperature and pressure, and influence a very small area.

Question 5.
What is a ‘rain shadow’ region?
Answer:

• The moist air is forced to rise over mountain.
• It gives heavy precipitation on the windward side.
• After that the air, which is devoid of moisture blows over leeward side.
• It does not give rain there. So this dry region is known as ‘rain-shadow’ region.

Question 6.
Discuss the cloud formation and various clouds.
Answer:

• Water vapour in the atmosphere attracts dust particles and condense as droplets.
• These droplets in millions and millions together appear like clouds.
• Clouds are different types based on their forms and heights.
• For examples, Cirrus clouds (at higher level), Cumulus clouds (at middle level), Stratus (at lower level) and nimbus (rain bearing and vertical clouds).

Question 7.
How many pressure belts do we have? And what are they?
Answer:
There are seven pressure belts on the earth’s surface. They are :

1. The equatorial low-pressure belt. (1)
2. The sub-tropical high pressure belts. (2)
3. The sub-polar low pressure belts. (2)
4. The polar high pressure belts. (2)

Question 8.
What is relative humidity?
Answer:
The realtive humidity is the ratio between

• The maximum water vapour that the air can hold and
• The actual amount of water vapour it holds.

Question 9.
What are planetary winds? How many types of winds are there?
Answer:
The winds that blow constantly, regularly above the world’s pressure belts are known as planetary winds. They are of three types :

1. Trade winds
2. Westerlies
3. Polar winds.

Question 10.
Write about local winds.
Answer:
The local winds blow due to local variation in the temperature of the area.
These winds are of two types. They are :
1. Hot local winds
2. Cold local winds.

1. Hot local winds :
Hot local winds raise the temperature of the area.

2. Cold local winds :
Cold local winds sometimes bring the temperature of the local area below the freezing points.
Ex : Mistral, Puna, Pampero, etc.

Question 11.
What is NASA?
Answer:
The space agency of USA is NASA, i.e., the National Aeronautics and Space Administration.

Question 12.
“The wind flows from high pressure areas to low pressure areas” – interpret the statement.
Answer:

• When any part of the earth heats up and causes low pressure, it means that there is more vacant space and less molecules.
• Now air from other parts where the pressure is higher moves towards this vacant place.
• It is not difficult for the wind to move along the earth’s surface and thus need not go too much against gravity any more.
• That is why the wind flows from high pressure areas to low pressure areas.

Question 13.
“Heat and pressure – If one increases the other decreases – this is called an inverse relationship” – Interpret the statement.
Answer:

• Due to the heating of the earth’s surface, the gas molecules are heated up, they get a lot of energy and start moving very fast.
• The pressure increases as the molecules will be pushing the object more.
• The energised molecules start flying off higher and higher.
• Now they have more energy to defy the pull of the earth.
• When more molecules go to higher reaches of the atmosphere, the place near the earth has less molecules, this means less pushing around or less pressure.
• Thus when it gets hot, the air pressure becomes low and when it becomes cool, the pressure increases.
• In simpler terms “If one increases the other decreases”-this is called an inverse relationship.

Question 14.
Nowadays there is great demand for energy. Conventional energy sources are depleting quickly. In the light of this, assess wind as alternate energy?
Answer:

• Nowadays there is great demand for energy and conventional energy sources are depleting quickly.
• In these situation wind energy is definitely an alternate energy source.
• Winds like planetary, which blow constantly and regularly are of great help in energy production.
• Wind energy is not an exhausting one like conventional resources.
• Winds of other nature like monsoon and local winds also come handy in energy production.

Question 15.
Observe the figure and answer the questions that follow.

1. To which pressure belts are the westerlies blowing?
Answer:
The westerlies are blowing towards sub-polar low pressure belts.

2. To which pressure belts are the easterlies blowing?
Answer:
The easterlies are blowingtowards sub-polar low pressure belts.

3. What are the winds that are blowing towards the equatorial Sow pressure belts?
Answer:
Trade winds are blowing towards the equatorial low pressure belts.

4. What is the other name for the equatorial low pressure belts?
Answer:
The equatorial low pressure belts are also known as “the equatorial doldrums” or ITCZ i.e., Inter-Tropical Convergence Zone.

5. Towards which direction (right or left) are the planetary winds blowing?
Answer:
The winds in the Northern hemisphere are deflecting towards right and the winds in the southern hemisphere are deflecting towards left due to coriolis effect.

Question 16.
Appreciate the role of winds in weather and climate patterns. Draw a parallel from history.
Answer:

• Winds play a very important role in the weather and climate patterns around the world.
• They have also played a very important role in history.
• For example, Vasco da Gama found sea route to India using winds to power his ships.
• He was able to transport and trade in spices with help of these winds.
• These winds are crucial for Portugese to rule over Goa.

Question 17.
Explain the measures to be taken to mitigate the cyclones.
Answer:

• Early warning systems are needed to be installed by the government.
• Government should inform people in advance about the possibility of disasters like cyclones.
• Government shall provide people with longterm security like strong roads, safe pucca houses for people of low land areas.
• Food, water and medical emergency teams should be kept ready whenever there is a forecast of cyclone.
• Close cooperation between people, Non-Governmental organizations and Government organizations are essential to mitigate cyclone affects.

These AP 9th Class Social Studies Important Questions 1st Lesson Our Earth will help students prepare well for the exams.

AP State Syllabus 9th Class Social 1st Lesson Important Questions and Answers Our Earth

9th Class Social 1st Lesson Our Earth 1 Mark Important Questions and Answers

Question 1.
Which continent is extended in four hemispheres In the given map. (SA-III : 2015 – 16)
Answer:

Africa continent.

Question 2.
What do you mean by anti meridian? (SA-III : 2016 – 17)
Answer:
The anti meridian is the meridian of longitude opposite the Prime-Meridian.

9th Class Social 1st Lesson Our Earth 2 Marks Important Questions and Answers

Question 1.
Draw the picture of the Globe and point out all the latitudes that are given special names on it. (SA-III : 2016 – 17)
Answer:

Question 2.
Why is it important to know the latitude and longitude of a place on map? How can it be useful? (SA-II : 2018 – 19)
Answer:
It is very important to know about latitudes and longitudes of a place by the following reasons.

• The particular location of a place on the earth can only be traced precisely with the help of latitude and longitude of that place.
• Latitude also help us in understanding the pattern of wind circulation on the global surface.
• Longitudes are useful to us to define the east-west position of a location on the planet.
• Longitudes are useful to us to know the time of the place.

Question 3.
Wegener hypothesised that the super continents of pangea broke up into two blocks –
1) Laurensia
2) Gondwana. It took millions of years for the continents to reach the present shapes and positions on the globe. (SA-I : 2018 – 19)
1) Laurensia : North America, Greenland, and all of the Eurasia north of Indian sub continent.
2) Gondwana : South America, Africa, Madagascar, India, Arabia, Malaysia, East Indies, Australia and Antartica.
Based on the above information given – answer the following questions.
a) Write any two land masses of present Asian continent which were formed from Gondwana?
b) From which block was the present Europe continent formed?
Answer:
a) India, Arabia, Malaysia, East Indies.
b) The present Europe continent was formed from Laurensia block.

Question 4.
If every state in India follows its local time then what problems will arise? (SA-I : 2019 – 20)
Answer:
If every state follows its local time, the following problems will arise :

• People travelling to different states would have to change their clocks too often.
• There would be confusion and chaos in the timings of railways, airlines, buses etc.
• The schedules of television shows, live shows and games, news etc. would be disrupted.

9th Class Social 1st Lesson Our Earth 4 Marks Important Questions and Answers

Question 1.
What is the difference between local time and standard time ? If every state follows its local time then what problems will rise in India? (SA-III : 2015 – 16)
Answer:
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 IST is 12.00 noon, the local of Mumbai is 39 minutes – IST = 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.

If every state follows its local time, a lot of serious problems would rise. Some of them are being discussed hereunder.

• At the time of national calamities and disasters, it is very difficult for the national government to make necessary emergency announcement.
• 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.
• It is very difficult for Televisions and Radios to follow a single schedule to broadcast their programmes.
• Railways faces a difficult problem in preparing a timetable for its trains that travel through many states.

Question 2.
Describe the internal structure of the earth. (SA-III : 2016 – 17) (SA-I : 2018 – 19)
Answer:
The earth is made up of three main layers.
A) Crust:

1. The outer part of the earth on which we live is called the crust.
2. While the earth was boiling in a molten form the lighter particles cooled at the top and formed the layer of crust.
3. The curst mostly consists of various kinds of rocks.
4. This layer goes up to a depth of 30 to 100 kms.

B) Mantle:

1. While the earth was boiling in a molten form the less heavier particles settled in the middle and formed the mantle.
2. The upper part of the mantle is a pliable layer over which the crust floats.
3. This layer consists mainly of chemicals called silicates.
4. It exists at the depths from 100 kms to 2900 kms.

C) Core:

1. While the earth was boiling in a molten form the heaviest substances formed core.
2. It is composed of dense and heavy substances like Iron and Nickel.
3. It exists at the depths from 2,900 kms to 6,376 kms.
4. It can be divided into two sub-layers.

a) Outer core :
This layer is composed of liquid metallic material like nickel and iron. It is 2,900 – 5,100 kms in thickness.

b) Inner core :
The solid inner core is made up of iron compounds and heavy substances like gold. It is 5,100 – 6,376 kms in thickness.

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

Question 1.
How can you say the man himself is responsible for environmental crises?
Answer:

• More than any other animal human beings have been trying to make the earth a better place to live in.
• Trying to change ourselves and our surroundings we have entered into conflict with other inhabitants of the earth.
• For long we’ve been exploiting the earth for its resources.
• The reckless exploitation of the earth resulted in environmental crises such as global warming and poisoning of our soils, water and air.
• Thus we can say man himself is responsible for environmental crises.

Question 2.
What were the initial ideas of people about the earth, the sun the moon and other astronomical bodies?
Answer:

• For thousands of years humans have been looking into the sky trying to understand objects that shine there.
• Initially, people thought that earth was firm and stationary and all others went round it.
• They also thought that the earth, the stars and the sun have been like this forever and will be like this forever without any change.

Question 3.
Write about the phases of evolution of facts, about the astronomical bodies their birth and growth.
Answer:

• Initially, people were of the view that the earth was firm and stationary and all the other bodies went round it.
• About five hundred years ago scientists concluded that the earth is not in the middle of everything.
• The earth actually moves round the sun and that the sun itself is also moving.
• The countless stars in the sky are actually so many suns.
• During the last hundred years or so people learnt the stars are born, they grow old and even die.
• Scientists even came to know that the stars are actually part of larger groups called galaxies.
• There are millions of galaxies in the universe.
• Now scientists are of the view that the universe itself started some 13.7 billion years ago with a Big Bang and it may end several billion years later.

Question 4.
How dkl the universe come into existence?
Answer:

1. The universe itself started some 13.7 billion years ago with a Big Bang.
2. From this Big Bang, several galaxies were formed.
3. Within these galaxies, stars were formed.
4. Planets were formed around stars and went around them.

However these astronomical changes take place over thousands and even millions of years.

Question 5.
Describe the process of evolution of the Earth.
(OR)
How did the earth come into existence and get its present form?
Answer:

• The earth began to form around four and a half billion years ago.
• It began as a ball of swirling dust and clouds and passed through a molten age.
• Gradually it grew in size.
• It was very hot and was in molten stage.
• The lighter particles cooled at the top and formed a layer of crust.
• Heavier particles formed the part of the molten core.
• As the earth’s interior cooled and contracted, the outer crust wrinkled, forming ridges and basins.
• The rain filled the basins and thus oceans formed.
• Slowly atmosphere developed and slowly life appeared on the earth.

Question 6.
How and when did the life appear on earth?
Answer:

• Different kinds of gases including water vapour formed the atmosphere on earth.
• Most of these gases were such that life as we know it today could not survive on it.
• Because it did not have oxygen necessary for life to survive.
• It took a long time for the air to develop.
• Then life appeared on oceans first.

It slowly evolved into diverse forms – plants, animals and human beings.

Question 7.
Are the shapes and positions of the continents fixed and permanent as they appear on the globe?
Answer:
The shapes and positions of the continents may seem fixed at the time scale of human experience. But on old earth continents have moved, collided, merged and then been torn apart again.

Mountains have risen and been razed to the ground, oceans have formed and dried up. Valleys have been carved and so during the course of earth’s eventful history. Alfred Wegener’s theory of Continental drift proves the same idea.

Thus the shapes and positions of the continents are not fixed and permanent.

Question 8.
Describe the theory of continental drift.
Answer:

• In 1912 Alfred Wegener propounded the theory of continental drift to describe the present arrangement of continents and ocean basins.
• He postulated a massive super continent Pangaea that existed 220 million years ago.
• Pangaea, the hypothetical continent, from which present continents originated by the drift from Mesozoic era to the present.
• Wegener hypothesized that the super continent of Pangaea broke up to from :
  a) Laurensia – consisting of present North America, Greenland and all of Eurasia north of Indian subcontinent and
  b) Gondwana land – consisting of present South America, Africa, Madagascar, Arabia, India, Malaysia, East Indies, Australia and Antarctica.
• These two blocks were separated by a long shallow inland sea called Tethys sea.
• It took millions of years for the continents to reach the present shapes and positions on the globe.
• Even today many of the continents are moving very slowly pushing each other.

Question 9.
What do you know about latitudes?
Answer:

• Latitudes are imaginary lines drawn around the earth.
• The word ‘latitude’ comes to us from the Latin word ‘iatitudo’ meaning width.
• Latitudes are also called parallels because they are parallel to each other.
• Latitudes are circles.
• Latitudes are expressed in degrees (°), minutes (‘) and seconds (“).
• Latitude values range from 0° t* 90° North (the North Pole) and 90° South (the South Pole).
• Thus there are 180° main latitudes (not counting the equator)
• Equator, the 0° latitude is the largest among all the latitudes.
• Latitudes are used together with the longitudes to locate a place on the earth.
• Latitudes are used to locate the climatic zones on the earth.

Question 10.
What do you know about longitudes?
Answer:

• Longitudes are imaginary lines connecting North and South’Poles.
• Longitudes are semi-circles.
• Longitudes are also called meridians because when the sun is overhead on a longitude at the time on that longitude it is noon (meridianus).
• There are 360 longitudes in total.
• The longitudes from 0° to 180° to the east are called eastern longitudes.
• The longitudes from 0° to 180° to the west are called western longitudes.
• 0° meridian is called the Prime meridian or Greenwich meridian.
• Longitudes are also expressed in degrees (°), minutes (‘) and seconds (“).

Question 11.
How are the time zones formed and why are they formed?
Answer:

• It takes 4 minutes for the sun’s position to move 1° of longitude.
• This means that the time is different for each degree of longitude.
• This can cause a lot of confusion.
• Therefore to end up this confusion the world is divided into 24 time zones.
• The width of each time zone is 15° of longitude.
• This means the difference between one time zone and the next is 1 hour.
• As you go from Greenwich meridian, you add time; as you go west of the Greenwich meridian you subtract time.

Question 12.
Why does every country have its own standard time?
Answer:

• The world is divided into 24 time zones.
• The width of each time zone is 15° of longitude.
• This means that the difference between one time zone and the next is one hour.
• Some countries would have more than one time zone with less than one hour division.
• This is considered too complicated to be useful.
• That is why some countries choose the time along one of the meridians that pass throught their territory and follow the time of that meridian for the whole country.
• This time is called standard time.

Question 13.
What is a Grid?
Answer:
A grid is a square 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’.

Question 14.
When it is 12 noon in Greenwich (0°), what is the local time at Mumbai (73° E)?
Answer:
Mumbai (73° E) : Local time at Mumbai is : 73 x 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.

Question 15.
When it is 12 noon in Greenwich (0°), what is the local time at Chicago (87°30′ W) ? Chicago (87°30‘ W) : Local time at Chicago is : 87°30‘ x 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.

Question 16.
When it is 12 noon in Greenwich (0°), what is the local time at Sydney (151° E)?
Answer:
Sydney (151° E): Local time at Sydney is 151° x4 = 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 17.
a) What are called ‘parallels’?
b) What are called ‘meridians’?
Answer:
а) Latitudes are called ‘parallels’,
b) Longitudes are called ‘meridians’.

Question 18.
What is the standard meridian of India?
Answer:
82°30′ Eastern longitude is the standard meridian of India.

Question 19.
If you were to travel from India to Japan. How would be the change in time?
Answer:

1. Japan is located in East to India.
2. If we travel to East, then we gain time as per East Gain Add (EGA).
3. India is in 5Vi hours time zone and Japan in 9 hours time zone.
4. Both are in eastern hemisphere. Thus we gain nearly 3% hours time.

Question 20.
How do you think human greed led to exploitation of the earth?
Answer:

• Human life on earth dates back to one lakh years, whereas formation of the earth was four and a half billion years ago.
• Man has constantly trying to change our surrounding to make it a better place to live in.
• He looked on earth as a storehouse of resources and making use of it, at will.
• Thus his greed led to exploitation of the earth.

Question 21.
Why do you think, it took so long time to understand the interior of the earth?
Answer:

• It is difficult for man to know directly about the Earth’s interior.
• So far man could dig a 3 km interior of the earth.
• He could send pipes upto a depth of 6K km.
• But, the radius of the earth is 6,440 km.
• Apart from this, if we go deep the earth-temperature raises at a rate of 1°C for every 32 meters.
• An estimated temperature at the centre of the interior of the earth is 6000°C.
• Thus man was unable to get direct information.
• So he need to rely on indirect sources like seismic waves etc.
• Thus it took so long time to understand the interior of the earth.

Question 22.
Describe the earth’s interior.
Answer:

1. The earth has a radius of 6440 km.
2. The temperature increases at a rate of 1°C for every 32 mts. of depth.
3. The temperature at the centre of the earth would be 6000° C.
4. As such the rocks will be in molten stage.
5. Pressure also increases when one goes deeper into the earth.
6. The earth is made up of three layers. They are : 1) Crust, 2) Mantle, 3) Core.
7. These layers differ from one another in thickness and also in their physical and chemical compositions.

Question 23.
What is “continental drift theory”? Explain.
(OR)
What is the “theory of continental drift”?
Answer:

• Alfred Wagener postulated the theory of continental drift.
• It explains the present arrangement of continents and ocean basins.
• He postulated a massive super continent called “Pangaea” which existed 220 million years ago.
• Present continents originated, by the drift from this “Pangaea”.
• Wagener hypothesised that the supercontinent of Pangaea broke up into two blocks
  1) Laurensia,
  2) Gondwana land.
• The two blocks were separated by a long shallow inland ocean called “Tethys”.
• It took millions of years for the continents to reach the present shape and position.

Question 24.
Differenciate between latitudes and longitudes.
Answer:

Latitudes	Longitudes
1. Latitude comes from a Latin word “Latitudo”, meaning width.	1. Longitude is derived from a Latin word “Longitudo”, meaning height.
2. The circles drawn parallel to the equator at 1° interval are known as latitudes.	2. The semicircles drawn connecting pole to pole are known as longitudes.
3. There are 180 latitudes excluding the equator.	3. There are 360 longitudes.
4. Every latitude must be designated with either “N” or “S” direction.	4. Every longitude must be designated with either “E” or “W” direction.
5. They are also known as “Parallels”.	5. They are also known as “Meridians”.
6. The climate of a place can be identified with the help of latitudes.	6. The differences in time can be calculated with the help of longitudes.

Question 25.
How many blocks did the Pangaea brake up into? What are they?
Answer:
The super continent of Pangaea was broke up into two blocks.
1) Laurensia:
Present N.America, Greenland and all of Eurasia, north of Indian subcontinent formed from it.

2) Gondwana land :
Present S.America, Africa, Madagascar, India, Arabia, Malaysia, East Indies, Australia and Antarctica formed from it.

Question 26.
How do you find a place in an atlas?
Answer:

1. We can find the information about a place in an atlas with the help of latitudes and longitudes.
2. Places are listed alphabetically at the back of the atlas.
   Ex : To locate “Visakhapatnam”.

Question 27.
What are longitudes? How many are there? Name some important longitudes.
Answer:

1. The semicircles connecting pole to pole are called longitudes.
2. They are 360 in number.
3. Some important longitudes are :
   a) Prime Meridian – 0° longitude
   b) International Date Line – 180° longitude

Question 28.
“For long we have looked at the Earth as a store house of resources, which we can exploit and use at will. Gradually we are realizing the fallacy of this view point” – Interpret the above statement.
Answer:
For long we have looked at the earth as a store house of resources. With this view we recklessly exploited the earth and are responsible to the destruction of forests, rivers, hills, fellow animals and even fellow humans. This resulted in the environmental crises such as global warming and poisoning of our soils, water and air.

But gradually we understand that the earthly resources are not infinite but finite and the environmental system is a closed one. So we should not use the natural resources indiscriminately.

If a man has to survive, he must derive something from the nature. The exploitation of minimum resources from the natural environment to fulfil the basic needs of human society would cause disequilibrium of some sort in the ecological balance resulting into environmental degradation and pollution. We should always use the natural resources in such a way that they are always at available in a desired quantity and quality.

Question 29.
“Today more than any other time we need to build a new understanding of the Earth, how it works and what we do on it and what we do with each other” – Interpret the above statement.
Answer:
In the decades of 1970s there emerged a concern about the fear of depletion of natural resources because of irrational and rapacious utilization of natural resources. This serious concern arises from the fact-rapid rate of rapacious exploitation of natural resources and modern production processes and advanced technologies. Thus the exploitation of natural resources has threatened the stability and survival of natural ecosystems and existence of several plant and animal species.

Hence today more than any other time we need to build a new understanding of the earth, how it works and what we do on it and what we do with each other.

Question 30.
Read the following para and answer the questions.
Scientists have figured out that the stars are actually part of larger groups called galaxies and that there are millions of such galaxies in the universe. Now, they are of the view that the universe itself started some 13.7 billion years ago with a ‘Big Bang’ and that it may end several billion years later.
1) What is a galaxy?
Answer:
A larger group of stars is called a galaxy.

2) When was the ‘Big Bang’ happened?
Answer:
‘Big bang’ was happened some IB.7 billion years ago.

3) How many galaxies are contemplated by scientists?
Answer:
Scientists contemplated that there are millions of galaxies in the universe.

4) When would be the end of the universe?
Answer:
The end of the universe would be after several billions of years.

Question 31.
What factors determine the number of standard times of countries?
Answer:
Countries which have much east-west extension will have a number of standard times.
Ex: Russia.

Question 32.
Identify other names of “Earth”.
Answer:
Bhoomi, Prudhvi, Dharithri, Dharani, Pudami, etc.

Question 33.

Layer of Earth	Depth	Composition
1. Crust	30 – 100 km	Various kinds of rocks
2. Mantle	100 – 2900 kms	Chemicals & Silicates
3. Outer core	2900-5100 kms	Nickel & Iron
4. Inner core	5100 – 6376 kms	Iron compounds & Gold

Observe the table and answer the following questions.
1) Which is uppermost layer of the interior of the earth?
Answer:
Crust is the uppermost layer of the interior of the earth.

2) What is the thickness of the core?
Answer:
The thickness of the core is 3476 kms.

3) Which layer is supposed to have more gold?
Answer:
The inner core is supposed to have more gold.

4) What is the radius of the earth?
Answer:
The radius of the earth is 6376 km.

Question 34.
Observe the following table and answer the questions given below.

What is the latitudinal value of “Equator”?
Answer:
The latitudinal value of Equator is “0°”.

2) What is the name given to 90° N and 90° S latitudes?
Answer:
90° N is called North pole and 90° S is called South pole.

3) What are the values of Arctic and Antarctic circles ?
Answer:
The value of Arctic circle is 6634° N.
The value of Antarctic circle is 6634° S.

4) In which hemisphere is the Arctic circle situated ?
Answer:
Arctic circle is in Northern hemisphere.

5) Which latitude does not have any direction?
Answer:
The Equator does not possess any direction.

Question 35.
One among our ‘environment crises’ is the poisoning of air. in light of this, how would you assess the Government of Delhi, deciding to allow vehicles with odd and even number plates on alternate days?
Answer:

• Air pollution is one among the environmental crises we face.
• Government of Delhi decided to allow the odd number plate vehicles to ply on the Delhi roads the other day.
• This alternate day journey provision definitely reduces the traffic congestion.
• It also promises in reduction of pollution.
• Already petrol vehicles ply on Delhi roads was banned.
• Compressed Natural Gas is the need of the hour.
• However, care must be taken to disallow everyone to have a vehicle with odd number and another with even.

Question 36.
Observe the following pictures.

a) What do the above pictures represent?
Answer:
The above pictures represent the stages of continental drift.

b) Look at the above picture “2” and identify the following.
1) India,
2) Africa,
3) Tethys sea

c) Identify.
i) South America in picture “3”.
ii) Antarctica in picture “4”.
Answer:

Question 37.
How can you say the Earth’s orbit is nearly circular but not exactly circular or an elongated oval path?
Answer:

• The orbit is the path of the Earth around the sun.
• The difference between earth’s farthest point (about 152 million km from the sun and the closest point 147 million km) is very small.
• Thus we can say the earth’s orbit is nearly circular but not exactly circular or an elongated oval path.

Question 38.
Prepare a palmphet on environmental crises.
Environment Crises
Answer:
For longtime man looked on earth as a store house of resources and tried to exploit at will. His reckless exploitation of earth has meant distruction of forests, rivers, hills, fellow animals and even fellow human beings.

Global warming, which is caused by the increased presence of green house gases like carbon dioxide, methane etc. It is resulting in melting of ice and submerging of low lands and coasts.

Soil pollution is caused by excessive use of chemicals, fertilizers and pesticides in agriculture and industrial waste deposition. Soil erosion is caused by excessive falling of trees and lack of pastures.

Water pollution is caused by routing of industrial wastes into water, usage of chemicals and pesticides etc. Air pollution is caused by the emissions from vehicles, air conditions etc.

Question 39.
Create visual representation to understand the time as described in the earth’s origin to your birth.
Answer:

These AP 9th Class Biology Important Questions 8th Lesson Challenges in Improving Agricultural Products will help students prepare well for the exams.

AP State Syllabus 9th Class Biology 8th Lesson Important Questions and Answers Challenges in Improving Agricultural Products

9th Class Biology 8th Lesson Challenges in Improving Agricultural Products 1 Mark Important Questions and Answers

Question 1.
What are the three types of methods to get high yield?
Answer:

• Improving high yielding varieties.
• Using high yield management methods.
• Crop protection management.

Question 2.
What are macro nutrients? Give examples.
Answer:
Minerals that required by plants in larger quantities are called macronutrients.
E.g.: Nitrogen, Phosphorous, Potassium, Sodium.

Question 3.
What are micronutrients? Give examples.
Answer:
Minerals required in small quantities are called micro nutrients.
E.g.: Iron, Manganese, Boron, Zinc, Copper, Molybdenum, Chlorine, etc.

Question 4.
What is the major difference between short term varieties and long term varieties?
Answer:
Short term varieties produce grains more than long term varieties.

Question 5.
Give Examples of chemical fertilizers.
Answer:
NPK, Urea and Superphosphate are the examples of chemical fertilizers.

Question 6.
What is a vermi compost?
Answer:
It is the product or process of composting using worms usually earthworms is called vermi compost.

Question 7.
What is Kharif crop? Give two examples.
Answer:
Cultivation and harvesting of any domesticated plant sown in the rainy season.
Ex : Paddy, sugarcane, maize, etc.

Question 8.
What is Rabi crop? Give two examples.
Answer:
Agricultural crops sown in winter and harvested in the summer season.
Ex : Wheat, barley, sesame, etc.

Question 9.
What are mixed crops? What is the advantage of growing mixed crops?
Answer:
If more than one crop is cultivated in the same field then it is called mixed crop. Because of mixed crop cultivation, the soil becomes fertile.

Question 10.
Give a list of green manure crops.
Answer:
Crops which are grown in field and can be ploughed back into the soil for soil fertility are called green manure crops.
Ex : Sanhemp, Lobia, Green gram, Kulthi, Berseem.

Question 11.
Write two uses of biofertilizers?
Answer:

• Biofertilizers are useful to maintain soil health and productivity.
• They synthesize nutrients from environment and soil.

Question 12.
What is the benefit of crop rotation?
Answer:
Crop rotation help the farmer by adding nutrients in the place of lost nutrients.

Question 13.
What is hybridization?
Answer:
Hybridization is a process to yield high yielding variety of crops.

Question 14.
What is GMS?
Answer:
Genetically Modified Seeds are called GMS.

Question 15.
What is NPK?
Answer:
NPK is the chemical proportion of nitrogen, phosphorus, and potash. These are partially or completely synthetic in origin.

Question 16.
What are weeds?
Answer:
Unwanted plants which are grown in the crop field along with cultivated crop.

Question 17.
What are insecticides? Give one example.
Answer:
These are the poisonous chemical substances which destroy the insects in the crop field. These are sprayed on the insect affected crops.

9th Class Biology 8th Lesson Challenges in Improving Agricultural Products 2 Marks Important Questions and Answers

Question 1.
What are the factors that cause increase in production of crop?
Answer:

• Production of crop depends on several factors.
• Only when there is a proper combination of several factors, the production can increase.
• Some of these factors include the kind of seeds planted, the properties of the soil, the availability and proper application of irrigation and fertilisers, the weather, con¬trolling insect attacks, the growth of seeds, and soon.

Question 2.
How to increase the food production?
Answer:

• Increasing the area of cultivated land.
• Increasing production in the existing land.
• Developing high yielding varieties.
• Alternative crops.
• Mixed crops.
• Cultivating short term crops like Rabi.

Question 3.
What is drip irrigation? What is its use?
Answer:

• Drip irrigation is a good practise in agriculture to prevent water wastage.
• In drip irrigation, water is supplied through small pipes.
• These pipes have small holes through which water passes drop by drop.
• Drip irrigation prevents wastage of water.

Question 4.
What is crop rotation? What is the benefit of crop rotation?
Answer:

• Crop rotation is the process in which one crop is followed by another crop on an agricultural field.
• When cereals are cultivated, more nutrients are utilised.
• If legumes are grown in the soil, less nutrients are utilised.
• Not only this, they synthesize some nutrients in the soil.

Question 5.
What is mixed crop? What are its uses?
Answer:
If more than one crop is cultivated in the same field then it is called mixed crop.
Uses:

1. Because of mixed crop cultivation the soil becomes fertile.
2. The nutrients which are used by one crop will be regained by cultivating another crop.
   E.g.: Soya grown along with Pea.
   Pea grown along with Green gram.
   Cotton grown along with Groundnut.

Question 6.
What are Green Manure Crops? Give examples.
Answer:

• Some crops are grown so that they can be ploughed back into the soil. They are known as Green manure crops.
• Some examples are berseem, kutthi, sunhemp, lobia, green gram, etc.

Question 7.
What are the functions of soil testing centre?
Answer:

• At these centres the soil technologist collects soil samples from fields and tests the fertility levels of soil.
• They give us knowledge about the soil.
• The testing centres are situated in division and district levels.

Question 8.
What is organic farming? What are its uses?
Answer:

• To maintain soil productivity organic farming came into existence.
• In this type of farming, farmers use natural manures and natural pest controlling methods and they also practise crop rotation and mixed crop systems.

Question 9.
What are the advantages of water shed management?
Answer:

• The water shed increases the moisture in the soil and prevents soil erosion as tree roots hold the soil firmly.
• When there are many trees close by as in a forest, all of them together hold large quantities of water.

Question 10.
Write briefly about hybridization.
Answer:

• By using hybridization methods the seeds with desired characters are developed.
• Biotechnologists develop hybrid varieties by crossing between two plants which have genetically different characters and they developing new variety with useful characters.
• The hybrid varieties that are produced by hybridization techniques are high yielding, disease-resistant can thrive on less rainfall, and will grow in acidic soils also.

Question 11.

Nutrient	Uses
Nitrogen	New leaves, flowers arise fast.
Phosphorous	Penetrates roots deep into the soil to absorb nutrients quickly.
Potassium	Resistance towards pests, increases the quality of smell, colour and taste of fruits.

Now answer the following questions.
1) Name the nutrient that is responsible for formation of new fruits and leaves.
2) Name the nutrient that is responsible for increase in the quality of smell, colour, and taste of fruits.
Answer:

1. Nitrogen
2. Potassium

Question 12.
Write the differences between mixed cropping and intercropping.
Answer:

Mixed cropping	Inter cropping
1. Seeds : Seeds of different crops are mixed before sowing.	1. Seeds of different crops are not mixed.
2. Pattern : There is no pattern of sowing.	2. The different crops are sown in sepa­rate rows and strips.
3. Inputs : Lesser inputs of irrigation and nutrients are required.	3. Requirement of inputs is compariti- vely more.

Question 13.
What are the advantages of hybridisation?
Answer:

• Due to this, high yielding plants are produced.
• It makes varieties in disease resistant plants.

Question 14.
Write the differences between manure and Fertilizer.
Answer:

Manure	Fertilizer
1. It consists of organic matter.	1. It consists of inorganic matter.
2. It is eco-friendly in nature.	2. It is not eco-friendly in nature.
3. It is prepared by animal excreta and plant wastes.	3. It is prepared commercially from chemicals.

Question 15.
Write the uses of manures.
Answer:
Manures helps in

1. improvement of soil structure
2. increase in water holding capacity
3. soil enrichment with nutrients

Question 16.
Why is soil replenishment essential? State one natural method of soil replefiishment.
Answer:
By growing same crop year after year in the same soil, the soil shows depletion in certain nutrients. Cropping in this field year after year leads to drop in production of crops. Crop rotation and mixed cropping are very useful in soil replenishment.

Question 17.
What are the major group activities involved for improving of crop yields?
Answer:

•  Crop variety improvement programme
• Crop production improvement
• Crop protection improvement

Question 18.
How do deficiency of nutrients affect the crop?
Answer:
Deficiency of any nutrient affects physiological process in plants including reproduction, growth, and disease resistance.

Question 19.
What are the uses of crop rotation?
Answer:

• Improves fertility of the soil.
• It minimises the pest diseases.
• It controls weeds.
• It avoids depletion of a particular nutrient from soil.

Question 20.
The fields, in which legumes are grown, get enriched with nitrogen why?
Answer:
The roots of legumes have nodules on their roots which fix the atmospheric nitrogen due to which the land gets enriched with Nitrogen. Therefore, legumes are grown in a season alternating between cereal crops such as wheat and millet.

Question 21.
What is drip irrigation?
Answer:
Drip irrigation is a practice in agriculture to prevent water wastage. In this method, water is supplied through small pipes. These pipes have small holes where water pass through drop by drop.

Question 22.
Write some suggestions to improve food production.
Answer:
We should use

1. High yielding seed
2. Suitable irrigation system
3. By using fertilizers and pesticides in a prescribed way
4. Right time of sowing seeds.

9th Class Biology 8th Lesson Challenges in Improving Agricultural Products 4 Marks Important Questions and Answers

Question 1.
Write a short note on organic manure.
Answer:

• The organic manure is produced by decaying the plant and animal wastes.
• The manure produced from decomposed plants and animal products has more organic material.
• This gives good nutrients to the soil. It makes the soil fertile.
• Because of humus, the natural manure, water holding capacity of soil is increased.
• Natural organic manures are generally divided into two types. One is concentrated organic manure and the other is macro organic manure.
• Groundnut, gingilli, castor, coconut, neem, jatropa seed powders are the examples of concentrated organic manures.
• Animal excreta, compost, deep hitter are the examples of macro organic manure.
• Nutrients are rich in the concentrated manures than in macro organic manures.
• Plant and animal residues in the field such as stalks and roots, cow dung, urine, etc as organic manure.

Question 2.
How is the natural manure Panchagavya is prepared?
(OR)
An Agricultural Officer who encourages Organic farming wants to demonstrate preparation of natural manure by using five main ingredients of cow products. Prepare a note on it as a lab record.
Answer:

• The main ingredients of Panchagavya are milk, curd, ghee, dung, and urine of cow.
• Mix cow dung and cow ghee.
• Settle it for four days. On the fifth day, add urine, milk, and curd of cow.
• Also add kallu, coconut water, and sugarcane juice to the mixture and then add banana paste.
• Settle it for ten days. Stir the material morning and evening.
• Then we will get panchagavya the only sprayer type of manure.
• 3% of panchagavya is helpful to grow crop with higher yielding.
• It is also used as food for hens and fish in ponds.

Question 3.
What are the uses of nitrogen, phosphorous, and potassium?
Answer:
Uses of nitrogen, phosphorous, and potassium :

Nutrient	Uses
Nitrogen	New leaves, flowers arise fast.
Phosphorous	Penetrates roots deep into the soil to absorb nutrients quickly.
Potassium	Resistance towards pests, increases the quality of smell, colour and taste of fruits.

Question 4.
What are bio-fertilizers? Give examples.
Answer:
Some microorganisms which are useful to synthesise nutrients from the environment or from soil to plants. These are called microbial cultures or bio-fertilizers.

Question 5.
How vermi compost is prepared?
Answer:

• Construct 10 × 1 × ½ metres vermi compost beds in sheds which protect these beds from direct sunlight and rain.
• Collect coconut, banana, and sugarcane leaves, coconut coir, and dry black gram plants.
• Made them into 3 to 4 inches layer. This layer was wet with water.
• Collect house hold waste of dry cattle dung from the village to fill the bed.
• After two weeks of making bed, they kept thousand earth worms per square meter and covered the bed with gunny bags to maintain 30/6 to 40/6 of moisture.
• After 60 days we can collect our first manure.
• Second time, we will get the manure within 40 to 45 days.
• Every year we get the manure 6 times from these beds.
• Thus, vermi compost is prepared.

Question 6.
How Green revolution has changed the life style of farmers in India?
Answer:

• By Green revolution, the production of crops has been increased tremendously.
• Agriculture has become an industry and provides new avenues for work and fulfilment. Ecological balance may occur by the product of the green revolution.
• The soil may become fertilizer dependent. Plants are more dependent on pesticides which affect soil fertility man and animal health.

9th Class Biology 8th Lesson Challenges in Improving Agricultural Products Important Questions and Answers

Question 1.
Absorption of salts by different crops (Units: Kg/Hectares/Season)

Nutrient	Uses
Nitrogen	New leaves, flowers arise fast.
Phosphorous	Helps roots to penetrates deep into the soil to absorb nutrients quickly.
Potassium	Resistance towards pests, increases the quality of smell, colour and taste of fruits.

a) In which crop new leaves arise fast? Why?
b) In which crop roots do not penetrate deep into soil?
c) Which crop show more resistance to pests? Why?
d) From the above table, cultivation of which crop yields more to farmer?
Answer:

1. Sugarcane crop. Because it utilise nearly 90% of Nitrogen. Nitrogen is responsible for formation of new leaves.
2. Millet crops.
3. Sugarcane
4. Sugarcane

Question 2.
How do you appreciate the role of earthworms in helping farmers?
Answer:

• Earthworms are known as “friends of farmers”.
• Earthworms make the soil loose and enables it to aerate.
• They make the soil rich with organic fertilizers and reduce the farmer’s investment on chemical fertilizers.
• They also help the farmer in improving the crop productivity and soil quality.

Question 3.
If a farmer cultivating one type of crop then what happend?
Answer:

1. The crop productivity decreases.
2. Soil fertility gradually decreases.
3. Attack of pests on crops will increase.

Question 4.
Read the paragraph carefully and answer the questions given below.
Generally farmers use synthetic pyrethroids like pesticides, insecticides to control pests on crops. Farmers are also using so many natural pest controlling techniques.
1. Which concept in agriculture explains the above information?
2. Name some synthetic pesticides and insecticides.
3. Distinguish between synthetic insecticides and natural insecticides.
4. Write about any two natural insect control methods.
Answer:

1. Crop protective methods.
2. D.A.P. super phosphate, D.D.T, Heptachlore.
3. Artificial pesticides are nothing but poisonous chemicals. They harm and kill the pests but also the useful friendly insects which are useful in pollination. Natural pesticides are the insects which feed on pests that destroy crops.
   Ex : Dragon fly, spiders, mirids, lady bird beetle.
4. a) By introducing “Bacillus thuringiensis” we can protect our crops,
   b) By adapting mixed crop cultivation we can reduce pests naturally.

Question 5.
The fields of Ramaiah and Somaiah are in the same area. Both cultivated the cotton crop. Ramaiah got good crop yield than Somaiah. Guess the reasons for low crop yield of Somaiah.
Answer:

• He selected high crop yield variety of cotton.
• He used better crop management methods for high yielding.
• He used better pest controlling method to get high crop yield.
• He used soil friendly fertilizers to get high yield of crop.

These AP 9th Class Biology Important Questions 7th Lesson Animal Behaviour will help students prepare well for the exams.

AP State Syllabus 9th Class Biology 7th Lesson Important Questions and Answers Animal Behaviour

9th Class Biology 7th Lesson Animal Behaviour 1 Mark Important Questions and Answers

Question 1.
What are the expressions of animals to protect themselves from predators?
Answer:
Hissing of snakes, barking of dogs, stiffing of nailed hair of hedgehog (mullapandi), bad flavour from skin of tasmanian devil etc., are all the expressions to protect them¬selves from predators.

Question 2.
Why fish do not need to learn how to swim?
Answer:
Swimming is an instinct behaviour to fish. Hence they don’t need to learn how to swim.

Question 3.
How can butterfly get to know about nectar?
Answer:
Butterfly gets to know about the nectar instinctively.

Question 4.
Who does teach a bird to make a nest?
Answer:
There is no need to teach the bird to make it’s nest, because it is an instinct behaviour.

Question 5.
Give two examples of reflexes.
Answer:

• Kicking out when the doctor taps your knee with a small hammer.
• Sudden closing of eyes when a bright light is flashed on your face.

Question 6.
Give one example of imprinting from your surroundings.
Answer:
Salmon bird goes back to its home stream to spawn.

Question 7.
Give one example for conditioning.
Answer:
A tiger in a circus learns to stand up on a chair and jump through a hop to receive a food treat.

Question 8.
Name the branch of zoology that deals with scientific and objective study of animal behaviour.
Answer:
Ethology.

Question 9.
Give one example for imprinting behaviour.
Answer:
Ducklings follow the first moving object they meet after hatching and treat it as their mother.

Question 10.
Give one example of instinctive behaviour.
Answer:
Building a nest by birds/climbing trees by monkeys/swimming of fish in a lake.

Question 11.
Name the scientist who studied animal behaviour – imprinting.
Answer:
Konard Lorenz.

Question 12.
What are the other behaviours we find in animals and give examples?
Answer:
Animals show the feelings like happiness, threat, fear, anger, sadness etc…..
Eg: After returning from fields in the evening cow licks its calf. It reflects it’s affection towards its body.

Question 13.
How Tasmanian Devil protects itself from enemies?
Answer:
By spraying bad odour through it’s body.

Question 14.
What is imitation?
Answer:
People often imitate each other. This can help them to learn new and useful skills. It may also lead them to certain unwanted behaviours like drinking, smoking etc…

Question 15.
How do cockroaches differentiate light and dark?
Answer:
Cockroaches have eyes that are adapted to sense the difference between daylight and dark. Their eyes have cells that perceive light.

Question 16.
What is a pheramone?
Answer:
It is secreted or excreted chemical that triggers a social response in the members of same species.
Eg : ants, honey bees…

Question 17.
What are primates?
Answer:
The group of mammals that includes humans and monkeys.

Question 18.
Name the animal on which Ivan Pavlov done his experiments.
Answer:
Dog.

Question 19.
Give two examples of conditioning.
Answer:

1. Electronic fence stop grazing animals straying.
2. Children come out of the classroom after hearing the school bell.

Question 20.
What is special about Beaver?
Answer:
Beaver is a mammal which lives in South America, builds dams across water streams. Stagnated water is the living home for Beavers family.

Question 21.
Give names of scientists of Ethology.
Answer:

1. Nikolas Tinbergen
2. Konard Lorenz
3. Karlvon Frisch

9th Class Biology 7th Lesson Animal Behaviour 2 Marks Important Questions and Answers

Question 1.
What do you mean by animal behaviour? What it indicates?
Answer:

• Animal behaviour is the scientific study of the wild and wonderful ways in which animals interact with either, with other living beings and with the environment.
• It explores how animals relate to their physical environment as well as to other organisms.
• It also includes topics such as how animals find and defend resources, avoid predators, choose mates, reproduce and care for their young.

Question 2.
What are the uses and loses of imitation in human behaviour?
Answer:

• Imitation can help us learn something new and useful, such as new skill in lessons, sports or at work.
• Imitation also leads us to show less useful or harmful behaviour.
• For example, young people may start smoking, drinking alcohol or taking drugs as a result of copying each other to fit in.
• But it is very dangerous for our health.

Question 3.
How conditioning can be used to change the behaviour of people by advertisers?
Answer:

• Advertisers are very skilled in changing the behaviour of people.
• They use pictures of their products which make them look glamorous or exciting, often by using famous actors or sportspeople.
• By associating the product with attractive images the advertisers are trying to set up a conditioned response to their product.
• People will respond positively and buy the product.

Question 4.
Explain about tagging.
Answer:

• Like birds some other animals also migrate over large distances to find food or nesting sites.
• Animals can be tagged by attaching tracking devices to them.
• Tagging lets the scientists follow the journeys the animals make.

Question 5.
Write the process of hiding food by Scrubjay bird.
Answer:

• A bird called scrubjay hides its food.
• An experiment proved that a scrubjay had hidden its food in presence of another bird.
• After some time it was found that the other bird had stolen it by fixing a plan.

Question 6.
Write about a mammal Beaver, which lives in North America.
Answer:

• Beaver a mammal which lives in North America builds dams across water streams.
• Beaver cut big trees by its sharp teeth to fell the trees across the stream.
• Then the beaver constructed nearly four feet wall by using twigs, stones and mud.
• Stagnated water is the living home for beavers family.

Question 7.
Give two examples for reflexes.
Answer:

• Closing of the eyes when there is anything threatening the eye.
• The contraction of pupil when bright light enters eye.
• Withdrawing our hand when we touch hot objects.
• We sneeze when something enter our nose.
• We cough when we inhale dust etc.

Question 8.
How squirrels cheat others?
Answer:
Squirrels hide their food in an interesting way. They always behave in such a manner that somebody is trying to steal their food. In order to misguide others they dig holes in many places and heap leaves to cover them. Most of the holes do not contain food. In this way they cheat others by making believe that these holes contain food.

Question 9.
How beetle protects itself from enemies?
Answer:
Beetle (or) Bombardie Beetle has two chemicals hydroquinone and hydrogen peroxide stored in it’s body. Whenever the beetle feels threatened these chemicals mix with some special enzymes and that heat up the liquids which gives bad smell from it’s body.

Question 10.
What are the amazing features of intelligence of Dolphins?
Answer:
Dolphins have great logical thinking power they could understand a code language if they are trained by practice. The trained dolphins bring ball from the tub and throw it again into the same tub. They remember the names by short whistle.

9th Class Biology 7th Lesson Animal Behaviour 4 Marks Important Questions and Answers

Question 1.
Write about the experiment conducted by Ivan Pavlov on conditioning.
Answer:

• Ivan Pavlov (1849 to 1936) was a Russian Scientist who has investigated conditioning.
• He discovered that dogs produced extra saliva when they were offered food.
• Pavlov noticed that they also did the same when the person who fed them came into the room, even if the person had not brought any food.
• Pavlov went on to ring a bell at the start of feeding time, and eventually, the dogs produced extra saliva when they heard the bell, before any food was brought.
• A dog salivating when it hears a bell is not a natural response.
• They would not do this without being conditioned to do so.
• The behaviour has been learned. It is called a conditioned response.

Question 2.
Describe the process of hiding food by squirrel.
Answer:

• Squirrels hide their food in a fascinating way.
• They always behave in such a man¬ner that somebody is trying to steal their food.
• In order to misguide others they dig holes in many places and heap leaves, starch etc., to cover them.
• Sometimes most of the holes does not contain any food.
• In this way they cheat others to make believe that these holes contain food.

Question 3.
How wasp (bee) construct hive and how it collects food?
Answer:

• Wasp is an intelligent bee which builds its home keeping in view its future needs.
• Wasp builds its hive on the walls by using mud.
• They select suitable mud for constructing its hive.
• After constructing its hive they search for food.
• They collect food material by injecting its venom (usually other larva) and kept in it its hive.
• Wasp lay its eggs on the food material, which it used as food for larva of wasps.

Question 4.
Who experimentally proved that Dolphins have logical thinking power? Write about the experiments.
Answer:

• Hermon proved that Dolphins have great logical thinking power.
• Hermon studied four bottle nose Dolphins at Kavalo Basin mammal Laboratory of Hawai Islands.
• He named four Dolphins as Akkikomoi, Phoenix, Allen and Hippo.
• Hermon could understand by his study that Dolphins can remember their names and understand a code language if they are trained by practice.
• For example, the closed fist shows a tub, raised arms show a ball and one hand raised tells ‘bring here’.
• If we show the above actions in a sequence, the Dolphins would bring the ball from the tub, if we reverse the actions they throw the ball into the tub.
• If a Dolphin of particular whistle is called all the Dolphins stare at, while the par¬ticular one comes to us.

Question 5.
Describe the wonder behaviour of an African parrot Alex.
Answer:

• In 1977, Ervin Pepperberg brought a parrot and trained it.
• Slowly he made it learn more than 100 words.
• He then arranged the words in a such a way that Alex can frame its own sentences.
• After some days, he showed Alex one yellow bowl and another yellow dish and it recognised similarities and differences between them.
• Alex even tried to teach other parrots of its group.
• Alex called apple as ‘Bannery’ because it tastes like a banana and look like a big cherry. Naming in this way is a sign of creativity in language.
• Before Alex’s death, it could even learnt up to 7th table.

9th Class Biology 7th Lesson Animal Behaviour Important Questions and Answers

Question 1.
Explain behavioural adaptations of animals using two examples.
Answer:

• Nesting of birds, selecting mates, forming flocks for protection from enemies are some examples for behavioural adaptations in animals.
• Beaver, a mammal which lives in North America builds dams across water streams and catch the fish and feeds it’s family.

Question 2.
What are the ways to observe the behaviour of animals? Explain any one of them with suitable examples.
Answer:

• Scientists observe the animal behaviour either directly or indirectly.
• Behaviour can be investigated in the field or in the laboratory.
• Scientists spend many hours watching and studying the behaviour of animals. Animals can signal to each other. For example, they may call each other to warn danger. Some of the scientists record and study them to work out what the signals mean.
• Scientists use tagging method to observe bird and animal migration. Animals can be ‘tagged’ by attaching tracking devices to them. This lets scientists follow the journeys the animals make.

Question 3.
What is Tagging? How it is useful to scientists?
Answer:

• Scientists use tagging method to observe bird and animal migration.
• Animals can be “tagged” by attaching tracking devices to them.
• This lets the scientists to follow the journeys the animals make.

Question 4.

Observe the figure and answer the following questions.
1) In which chamber more cockroaches are there?
2) In which chamber less cockroaches are there?
3) What are the conditions of chamber that live more cockroaches?
4) How the behaviour of cockroaches?
Answer:

• Dark and damp conditions.
• Light and dry chamber.
• Damp and dark condition.
• Cockroaches searched for their favourite conditions and reached the dark damp chamber.

Question 5.
Observe the picture and answer the following.

a) What is the aim of the experiment?
b) Write about the behaviour of cockroaches.
c) Write down the differences of situation provided between two chambers having less and more cockroaches.
d) What will happen if you put rats instead of cockroaches in the above room?
Answer:
a) To study the behaviour of cockroaches.

b) Cockroaches selected their favourite conditioned chamber – dark and damp. In these conditions only cockroaches can survive.

c) The experimental box is divided into a choice of chamber with four different conditions. They are
a) light and dry
(b) light and humid
(c) dark and dry
(d) dark and humid.
Finally the cockroaches reached dark and humid chamber.

d) Rats also choose dark and damp chamber. Because darkness enable them to escape from predators and damp conditions make favour to maintain body temperature.

Question 6.
Suppose you were a quiz master for biology round in an event. Prepare some questions to ask about “Instinct” and “Imitation” in that event.
Answer:

• Birds fly in the sky – which type of animal behaviour is this?
• Ramu saw some ducklings following a hen. He was amazed to see this. Which type of animal behaviour is this?