Chemical Effects of Electric Current Class 8 MCQ Questions

MCQ on Chemical Effects of Electric Current Class 8

Choose the correct answer.

Question 1.
Which of the following is a poor conductor of electricity ?
A) copper
B) iron
C) saltwater
D) air
Answer:
D) air

Question 2.
Which of the following is a good conductor of electricity ?
A) copper
B) glass
C) pure water
D) air
Answer:
A) copper

Question 3.
Which of the following is an alternative to get accurate result when testing for the conductivity of electricity by using a tester?
A) tube
B) halogen
C) LED
D) CFL
Answer:
C) LED

Question 4.
Which of the following liquid is a good conductor of electricity?
A) sugar solution
B) coconut oil
C) pure water
D) vinegar
Answer:
D) vinegar

Question 5.
A tester with a magnetic needle compass can show the deflection in
A) sugar solution
B) coconut oil
C) pure water
D) lemon juice
Answer:
D) lemon juice

Question 6.
A tester with a LED can glow in
A) salt solution
B) acids
C) bases
D) above all
Answer:
D) above all

Chemical Effects of Electric Current Class 8 MCQ Questions

Question 7.
LED means
A) light emitting device
B) light emitting diode
C) light effect diode
D) low emitting diode
Answer:
B) light emitting diode

Question 8.
Which of the following tester can work even in flow of small currents?
A) bulb tester
B) LED tester
C) compass tester
D) B and C
Answer:
D) B and C

Question 9.
The longer lead of LED is always connected to the …….. terminal of the battery.
A) positive
B) negative
C) A or B
D) none of the above
Answer:
A) positive

Question 10.
If the tester of magnetic compass shows deflection in liquids then the liquid is ……….
A) a poor conductor
B) a good conductor
C) insulator
D) A or B
Answer:
B) a good conductor

Question 11.
The tester of magnetic compass does not show deflection in
A) sea water
B) tap water
C) distilled water
D) salt water
Answer:
C) distilled water

Question 12.
………., when dissolved in distilled water, makes it a good conductor.
A) vinegar
B) caustic soda
C) common salt
D) above all
Answer:
D) above all

Chemical Effects of Electric Current Class 8 MCQ Questions

Question 13.
The gas releases when electricity is passed through water
A) oxygen
B) hydrogen
C) both A and B
D) A or B
Answer:
C) both A and B

Question 14.
Who had shown that if electrodes were immersed in water and a current was passed, bubbles of oxygen and hydrogen were produced ?
A) William Nicholson
B) William Nicol
C) Antoine Lavoisier
D) None
Answer:
A) William Nicholson

Question 15.
The passage of an electric current through a conducting solution causes
A) bubbles at electrodes
B) chemical effect
C) both A and B
D) none
Answer:
C) both A and B

Question 16.
When electricity is passed through water ……………….. bubbles formed on the electrode connected to the positive terminal of the battery.
A) oxygen
B) hydrogen
C) both A and B
D) A or B
Answer:
A) oxygen

Question 17.
The gas releases when electricity is passed through water
A) oxygen
B) hydrogen
C) both A and B
D) A or B
Answer:
C) both A and B

Question 18.
The ……………….. colour spot appears when electricity is passed through the potato.
A) yellowish red
B) greenish blue
C) black and white
D) violet
Answer:
B) greenish blue

Chemical Effects of Electric Current Class 8 MCQ Questions

Question 19.
The greenish blue colour spot appears at …………….. terminal when electricity is passed through the potato.
A) positive
B) negative
C) both A and B
D) A or B
Answer:
A) positive

Question 20.
Which of the following is not an application of electroplating ?
A) rold gold jewellery
B) chromium coating on cycle handles
C) nickel coating on taps
D) painting on iron grills
Answer:
D) painting on iron grills

Question 21.
When electric current is passed through the copper sulphate solution, copper sulphate dissociates into ……………………… .
A) copper and carbon
B) copper and oxide
C) copper and sulphate
D) copper and hydrogen
Answer:
C) copper and sulphate

Question 22.
When electric current is passed through the copper sulphate solution, free copper deposits on the …………………. terminal.
A) positive
B) negative
C) A or B
D) on both positive and negative
Answer:
B) negative

Question 23.
The process of depositing a layer of any desired metal on another material by means of electricity is called
A) electroplating
B) electrolysis
C) photoelectric
D) electromagnetism
Answer:
A) electroplating

Question 24.
Generally …………………… plating is done on many objects such as car parte, bath taps, kitchen gas burners, bicycle handlebars, wheel rims and many others.
A) chromium
B) carbon
C) zinc
D) tin
Answer:
A) chromium

Chemical Effects of Electric Current Class 8 MCQ Questions

Question 25.
Property of Chromium is
A) shiny appearance
B) does not corrode
C) resists scratches
D) above all
Answer:
D) above all

Question 26.
…………… cans, used for storing food, are made by electroplating.
A) Chromium
B) Carbon
C) Zinc
D) Tin
Answer:
D) Tin

Question 27.
Coating of ………………… on Iron is used in bridges and automobiles to provide strength.
A) chromium
B) carbon
C) zinc
D) tin
Answer:
C) zinc

Question 28.
In the electroplating factories the disposal of the used ………………. is a major concern.
A) conducting solution
B) electricity
C) depositing metal
D) electrodes
Answer:
A) conducting solution

Question 29.
Rold gold jewellery are made in the process of
A) electroplating
B) electrolysis
C) photoelectric
D) electromagnetism
Answer:
A) electroplating

Question 30.
Identify the poor conductor among the following.
A) Salt solution
B) Sugar solution
C) Base
D) Acid
Answer:
B) Sugar solution

Chemical Effects of Electric Current Class 8 MCQ Questions

Question 31.
Prem set up an experiment as shown below.
Chemical Effects of Electric Current Class 8 MCQ Questions 1
He found that the bulb glowed. Which of the following actions would result in the bulb NOT glowing ?
A) Adding a few drops of sulphuric acid to the salt water
B) Replacing the carbon rods with copper plates
C) Dropping some metal coins into the salt water
D) Replacing the salt water with distilled water
Answer:
D) Replacing the salt water with distilled water

Fill in the blanks.

1. Some liquids are good conductors of electricity and some are …………………. . conductors.
Answer:
poor

2. Most liquids that conduct electricity are solutions of …………………. .
Answer:
acids, bases and salts

3. The passage of an electric current through a conducting liquid causes chemical reactions. The resulting effects are called …………………. of currents.
Answer:
chemical effects

4. The process of depositing a layer of any desired metal on another material, by means of electricity, is called ………………… .
Answer:
electroplating

5. LED means ………………….
Answer:
Light Emitting Diode

Chemical Effects of Electric Current Class 8 MCQ Questions

6. Jewellery makers electroplate silver and gold on …………………. expensive metals.
Answer:
less

Match the following.

Question 1.
Match the following and choose the correct option.

Group – A Group – B
i) Poor conductor a) milk
ii) Good conductor b) silicon
c) pure water

Answer:
i – c, ii – a

Group – A Group – B
i) Poor conductor a) milk
ii) Good conductor c) pure water

Question 2.
Match the following and choose the correct option.

Group – A Group – B
i) Chromium a) cycle handle bars
ii) Tin b) food storage cans
c) air

Answer:
i – a, ii – b

Group – A Group – B
i) Chromium a) cycle handle bars
ii) Tin b) food storage cans

Chemical Effects of Electric Current Class 8 MCQ Questions

Question 3.
Match the following and choose the correct option.

Group – A Group – B
i) Chemical effect a) electroplating
ii) Heating effect b) electromagnet
c) electric bulb

Answer:
i – a, ii – c

Group – A Group – B
i) Chemical effect a) electroplating
ii) Heating effect c) electric bulb

8th Class Physical Science Bit Bank

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