Current Electricity Quiz - CBSE Class 12 Physics

Free practice quiz: Current Electricity (CBSE Class 12 Physics). 21 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This CBSE Class 12 Physics practice quiz has 21 multiple-choice questions on Current Electricity, and 21 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. What is the SI unit of electric current?

   1. Volt
   2. Ampere
   3. Ohm
   4. Coulomb
   Show answer

   Answer: B. Ampere

   The SI unit of electric current is the ampere (A), which measures the rate of flow of electric charge.

2. How does the resistance of a conductor change with temperature?

   1. It always increases
   2. It always decreases
   3. It remains constant
   4. It depends on the material
   Show answer

   Answer: D. It depends on the material

   The resistance of a conductor changes with temperature; for most metals it increases, but for some materials like semiconductors, it can decrease.

3. Explain the principle behind a potentiometer.

   1. Ohm's law
   2. Kirchhoff's laws
   3. Conservation of charge
   4. Comparison of potential drops
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   Answer: D. Comparison of potential drops

   A potentiometer compares the potential drop across an unknown resistance with that across a known resistance to determine the unknown resistance.

4. Derive an expression for the equivalent resistance of two resistors connected in series.

   1. R = R1 + R2
   2. R = R1R2/(R1 + R2)
   3. R = R1 - R2
   4. R = R1/R2
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   Answer: A. R = R1 + R2

   In a series connection, the same current flows through both resistors. The total voltage is the sum of the individual voltage drops across each resistor, leading to R = R1 + R2.

5. Explain the concept of electric mobility.

   1. The ratio of drift velocity to the electric field
   2. The ratio of electric field to drift velocity
   3. The product of drift velocity and electric field
   4. The ratio of current to electric field
   Show answer

   Answer: A. The ratio of drift velocity to the electric field

   Electric mobility is a measure of how easily a charge carrier moves through a material under the influence of an electric field.

More questions in this quiz

Answers and explanations are in the full quiz.

1. What is Ohm's law?
2. Define resistance.
3. What is the effect on the current if the resistance of a conductor is doubled while the voltage remains constant?
4. State Kirchhoff's first law.
5. State Kirchhoff's second law.
6. What is the purpose of a Wheatstone bridge?
7. What is a galvanometer?
8. How is a galvanometer converted into an ammeter?
9. How is a galvanometer converted into a voltmeter?
10. Derive an expression for the equivalent resistance of two resistors connected in parallel.
11. Explain the concept of drift velocity.
12. What is the relationship between current, drift velocity, and the number density of charge carriers?
13. Describe the temperature dependence of resistivity for a semiconductor.
14. Explain the phenomenon of superconductivity.
15. Derive an expression for the internal resistance of a cell using a potentiometer.
16. A network of resistors is connected to a battery. How would you use Kirchhoff's laws to find the current flowing through each resistor?

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