Do liquids conduct electricity? - class-VIII

Understanding electrical conductivity in liquids, including the role of salts, acids, and bases, and methods for testing conductivity.

39 Questions Published

Questions

Question 1 Multiple Choice (Single Answer)

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:

  1. liquid $A$ is a better conductor than liquid $B$
  2. liquid $B$ is a better conductor than liquid $A$
  3. both liquids are equally conducting
  4. conducting properties of liquid cannot be compared in this manner
Question 2 Multiple Choice (Single Answer)

Solutions of acids and bases are generally :

  1. good conductors of electricity
  2. good conductors of heat
  3. good conductor of both heat and electricity
  4. none of the above
  5. all
Question 3 Multiple Choice (Single Answer)

Which solution will conduct the current?

  1. Sugar in water
  2. Sugar in ethanol
  3. Iodine in ethanol
  4. $MgCl _2$ in water
Question 4 Multiple Choice (Multiple Answers)

Which statements about conductivity of distilled water are correct?

  1. It possesses almost non-conducting nature
  2. It is obtained by distillation of water several times
  3. It is contaminated with little acid
  4. None of the above
Question 5 Multiple Choice (Single Answer)

The best conductor of electricity is a 0.1 M solution of :

  1. boric acid
  2. sulphuric acid
  3. acetic acid
  4. propionic acid
Question 6 Multiple Choice (Single Answer)

Pure water is a ________ conductor of electricity.

  1. good
  2. bad
  3. semi
  4. none of the above
Question 7 Multiple Choice (Single Answer)

Which of the following statements is false?

  1. Vegetables conduct electricity
  2. Passage of electric current will not change the colour of a solution
  3. An electrode conducts electricity
  4. Electroplating is one of the applications of chemical effects of electrical current
Question 8 Multiple Choice (Single Answer)

What happens when you join the free ends of the tester for more than a few minutes?

  1. Cells of the battery will drain quickly.
  2. The current will not be able to pass.
  3. There would be no conduction of electricity.
  4. All of the above
Question 9 Multiple Choice (Single Answer)

Which of the following statement is correct while conduction of electricity in lemon juice?

  1. The liquid (lemon juice) allows the electric current to pass through. Hence, the circuit of tester is complete.
  2. The current flows in the circuit of the tester.
  3. The bulb glows which indicates lemon juice is a good conductor of electricity.
  4. All of the above
Question 10 Multiple Choice (Single Answer)

Which of the following is a poor conductor of electricity?

  1. Air
  2. Tap water
  3. Iron
  4. Silver
Question 11 Multiple Choice (Single Answer)

Which of the following devices can be used to detect a weak current?

  1. Use of electric bulb in tester.
  2. Use of LED in tester.
  3. A tester using magnetic effects of current.
  4. Both B and C
Question 12 Multiple Choice (Single Answer)

When the liquid between two ends allow electric current, then :

  1. bulb of tester glows
  2. only heating of the tester takes place
  3. bulb of the tester does not glow
  4. none of the above
Question 13 Multiple Choice (Single Answer)

When salt is dissolved in distilled water, we obtain salt solution which is a / an :

  1. conductor of electricity
  2. insulator of electricity
  3. motor of electricity
  4. filament of electricity
Question 14 Multiple Choice (Single Answer)

Which of the following might be the reason that the current in the circuit is weak?

  1. Circuit of the tester might not be complete.
  2. The material may not be able to conduct electricity as easily as metals.
  3. The circuit of the tester is complete but still the bulb does not glow.
  4. Both A and B
Question 15 Multiple Choice (Single Answer)

Which of the following is not true about LED?

  1. There are two wires (called leads) attached to an LED.
  2. While connecting to a circuit, the longer lead of LED is always connected to the positive terminal of the battery.
  3. While connecting to a circuit, the shorter lead of LED is always connected to the positive terminal of the battery.
  4. LED can be used to detect weak current.
Question 16 Multiple Choice (Single Answer)

Which of the following would show deflection in the compass needle, the moment you dip the free ends of the tester?

  1. Tap water, vinegar
  2. Tap water, vegetable oil
  3. Tap water, honey
  4. Vegetable oil, honey
Question 17 Multiple Choice (Single Answer)

What happens when the current passing through the circuit is too weak?

  1. The filament does not get heated sufficiently and the bulb does not glow.
  2. The filament gets heated but the bulb does not glow.
  3. The filament does not get heated but the bulb glows.
  4. The filament gets heated and the bulb glows.
Question 18 Multiple Choice (Single Answer)

Which of the following statement(s) is correct while conducting electricity through vegetable oil?

  1. The liquid (vegetable oil) allows the electric current to pass through. Since, it is a good conductor of electricity.
  2. The circuit of the tester is complete but the bulb does not glow.
  3. The circuit of the tester is not complete and hence the bulb does not glow.
  4. Both A and B
Question 19 Multiple Choice (Single Answer)

It is not safe to carry out electrical repair works outdoor during rain because :

  1. rainwater is a good conductor of electricity
  2. rainwater contains mineral salts
  3. rainwater is a poor conductor of electricity
  4. both A and B
Question 20 Multiple Choice (Single Answer)

In LEDs, the longer lead is connected to ................ and the shorter lead is connected to .................. .

  1. negative terminal; positive terminal
  2. positive terminal; negative terminal
  3. negative terminal; neutral terminal
  4. positive terminal; neutral terminal
Question 21 Multiple Choice (Single Answer)

Which of the following, when dissolved in distilled water, makes it a good conductor?

  1. Potassium iodide
  2. Common salt
  3. Potassium dichromate
  4. All of the above
Question 22 Multiple Choice (Single Answer)

LED stands for :

  1. light emitting diode
  2. loose emitting diode
  3. light emission device
  4. light emitting device
Question 23 Multiple Choice (Single Answer)

LED is better than bulb to use in a tester as :

  1. it glows even when weak current passes through it.
  2. it emits more light.
  3. it is cheaper.
  4. all of the above
Question 24 Multiple Choice (Single Answer)

When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection due to:

  1. electrical effect
  2. mechanical effect
  3. magnetic effect
  4. lighting effect
Question 25 Multiple Choice (Single Answer)

Which of the following solution will not make the bulb glow?

  1. Copper sulphate
  2. Sodium chromate
  3. Potassium dichromate
  4. Sugar
Question 26 Multiple Choice (Single Answer)

When electric current passes through the filaments of a bulb, it starts emitting light due to :

  1. heating effect of electric current.
  2. magnetic effect of electric current.
  3. chemical effect of electric current.
  4. lighting effect of electric current.
Question 27 Multiple Choice (Single Answer)

The chemical effect produced by an electric current depends on:

  1. the nature of electrode
  2. the tester
  3. the conducting solution
  4. none of the above
Question 28 Multiple Choice (Single Answer)

Sea water is a good conductor of electricity but distilled water is not because :

  1. sea water contains mineral salts.
  2. distilled water contains mineral.
  3. both A and B
  4. none of the above
Question 29 Multiple Choice (Single Answer)

A tester is used to check the conduction of electricity through two liquids, labelled A and B. It is found that the bulb of the tester glows brightly for liquid A while it glows very dim for liquid B. You would conclude that :

  1. liquid $A$ is a better conductor than liquid$ B$
  2. liquid $B$ is a better conductor than liquid $A$
  3. both liquids are equally conducting
  4. conducting properties of liquid cannot be compared in this manner.
Question 30 Multiple Choice (Single Answer)

$H _2SO _4$ solution attached to a bulb in a beaker:

  1. cannot light the bulb
  2. can light the bulb
  3. diffuses the bulb
  4. none of above
Question 31 Multiple Choice (Single Answer)

Statement 1:  A solution of NaCI will conduct electricity. 
Statement 2:  NaCI will not form ions in solution. 

  1. Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.
  2. Both the Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.
  3. Statement 1 is correct but Statement 2 is not correct.
  4. Statement 1 is not correct but Statement 2 is correct.
  5. Both the Statement 1 and Statement 2 are not correct.
Question 32 Multiple Choice (Single Answer)

Which of the following is a poor conductor of electricity?

  1. Distilled water
  2. Tap water
  3. Sea water
  4. Drinking water
Question 33 Multiple Choice (Single Answer)

What make(s) water conducting?

  1. Salts
  2. Hydrogen
  3. Oxygen
  4. None of the above
Question 34 Multiple Choice (Single Answer)

Most liquids that conduct electricity are solutions of :

  1. acids
  2. bases
  3. salts
  4. all of the above
Question 35 Multiple Choice (Single Answer)

Which of the following is free of salts?

  1. Distilled water
  2. Sea water
  3. Tap water
  4. All of the above
Question 36 Multiple Choice (Single Answer)

Which of the following is used to detect the current?

  1. Tester
  2. LED
  3. Compass needle
  4. All of the above
Question 37 Multiple Choice (Single Answer)

Electric circuit provides a complete path for :

  1. solution to flow
  2. metal to flow
  3. neutron to flow
  4. current to flow
Question 38 Multiple Choice (Single Answer)

Water obtained from which of the following sources is a good conductor of electricity?

  1. Tap
  2. Ponds
  3. Wells
  4. All of the above
Question 39 Multiple Choice (Single Answer)

Which of the following is a good conductor of electricity?

  1. Sugar solution
  2. Oil
  3. Distilled water
  4. Tap water