CBSE Questions for Class 8 Physics Chemical Effects Of Electric Current Quiz 3 - MCQExams.com

The chemical effect produced by an electric current depends on:
  • the nature of electrode
  • the tester
  • the conducting solution
  • none of the above
Which of the following devices can be used to detect a weak current?
  • Use of electric bulb in tester.
  • Use of LED in tester.
  • A tester using magnetic effects of current.
  • Both B and C
Which of the following statement is correct while testing for conduction of electricity in lemon juice using an LED tester?
  • The liquid (lemon juice) allows the electric current to pass through. Hence, the circuit of tester is complete.
  • The current flows in the circuit of the tester.
  • The bulb glows which indicates lemon juice is a good conductor of electricity.
  • All of the above
Which of the following would show deflection in the compass needle, the moment you dip the free ends of the tester?
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  • Tap water, vinegar
  • Tap water, vegetable oil
  • Tap water, honey
  • Vegetable oil, honey
In the experiment to test for conduction of electricity through potato, which of the following observations indicate that a potato is a conductor of electricity?
  • Greenish blue spot on potato around one wire.
  • Greenish blue spot on potato around both wires.
  • Blue color spot on potato around one wire.
  • Blue color spot on potato around both wires.
If electrodes are immersed in water and a current was passed, bubbles of ___________ and __________ are produced.
  • oxygen and carbon dioxide
  • oxygen and hydrogen
  • hydrogen and carbon dioxide
  • nitrogen and carbon dioxide
LED is better than bulb to use in a tester as :
  • it glows even when weak current passes through it.
  • it emits more light.
  • it is cheaper.
  • all of the above
In the experiment to test for conduction of electricity through a potato, the greenish blue color spot on the potato is useful in identifying :
  • the positive terminal
  • the negative terminal
  • both A and B
  • neither A nor B
Why do jewellery makers electroplate gold or silver on metals? 
  • To protect it from corrosion.
  • To prevent spoilage of jewellery.
  • To make it shine.
  • To reduce cost.
Which of the following is true during electroplating?
  • The metal gets transferred from one electrode to another.
  • The metal gets deposited from positive terminal of a battery to negative terminal of the battery.
  • Some amount of metal gets dissolved in the solution of the electrolyte.
  • All of the above
Which of the following gas is formed at the electrode, connected to the positive terminal of the battery?
  • Nitrogen gas
  • Hydrogen gas
  • Oxygen gas
  • Carbon dioxide gas
Which of the following gas is formed at the electrode connected to the negative terminal of the battery?
  • Nitrogen gas
  • Hydrogen gas
  • Oxygen gas
  • Carbon dioxide gas
Which of the following is a chemical effect of electric current?
  • Formation of gas bubbles on the electrodes
  • Change of color of solution
  • Deposition of metals on the electrodes
  • All of the above
Which of the following is added to make the copper sulphate solution more conducting?
  • Hydrochloric acid
  • Sulphuric acid
  • Nitric acid
  • Carbonic acid
Assertion:Chromium plating is done on many objects like car parts, wheel rims and bath taps.
Reason:The chromed layer can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness.
  • Assertion is correct and Reason is incorrect
  • Assertion is incorrect and Reason is correct
  • Both Assertion and Reason is correct and Reason is the correct explanation of Assertion
  • Both Assertion and Reason is correct but Reason is not the correct explanation of Assertion
When electric current is passed through water, hydrogen is deposited over :
  • positive pole
  • negative pole
  • no dissociation
  • both the poles
Which of the following is an example of electroplating?
  • Coating of chromium on many objects such as bath taps, car parts, etc.
  • Coating of gold or silver on less expensive metals
  • Coating of zinc on tin to make cans
  • All of the above
When electric current is passed through water,  dissociation is indicated  __________.
  • in the form of bubbles
  • by color change
  • both a and b
  • none of above
Chemical effect of electric current may cause :
  • formation of gas bubbles at the electrodes
  • deposit of metal on the electrodes
  • change in colour of the solution
  • all of above
A tester is used to check the conduction of electricity through two liquids, labeled $$A$$ and $$B$$. It is found that the bulb of the tester glows brightly for liquid $$A$$ while it glows very dimly for liquid $$B$$. You would conclude that:
  • liquid $$A$$ is a better conductor than liquid $$B$$
  • liquid $$B$$ is a better conductor than liquid $$A$$
  • both liquids are equally conducting
  • conducting properties of liquid cannot be compared in this manner
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