Capacitance Quiz - CBSE Class 12 Physics

Free practice quiz: Capacitance (CBSE Class 12 Physics). 19 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This CBSE Class 12 Physics practice quiz has 19 multiple-choice questions on Capacitance, and 19 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 capacitance?

   1. The ability of a capacitor to store charge
   2. The rate of flow of charge
   3. The force exerted on a charge
   4. The resistance to the flow of charge
   Show answer

   Answer: A. The ability of a capacitor to store charge

   Capacitance is the ability of a capacitor to store electrical energy in an electric field.

2. What is the effect on the capacitance of a parallel plate capacitor if the distance between the plates is doubled?

   1. Capacitance is doubled
   2. Capacitance is halved
   3. Capacitance remains unchanged
   4. Capacitance is quadrupled
   Show answer

   Answer: B. Capacitance is halved

   The capacitance of a parallel plate capacitor is inversely proportional to the distance between the plates. Doubling the distance halves the capacitance.

3. A capacitor is charged to a potential difference of 100V and stores 200 μJ of energy. What is its capacitance?

   1. 0.4 μF
   2. 2.5 μF
   3. 40 μF
   4. 25 μF
   Show answer

   Answer: A. 0.4 μF

   The energy stored in a capacitor is given by U = (1/2)CV². Therefore, C = 2U/V² = 2(200 x 10⁻⁶ J) / (100 V)² = 0.4 x 10⁻⁶ F = 0.4 μF

4. Explain the concept of dielectric breakdown.

   1. The process where a dielectric material becomes a conductor
   2. The process where a dielectric material loses its insulating properties under a high electric field
   3. The process where a dielectric material becomes magnetized
   4. None of the above
   Show answer

   Answer: B. The process where a dielectric material loses its insulating properties under a high electric field

   Dielectric breakdown is the phenomenon where a dielectric material, under a sufficiently strong electric field, loses its insulating properties and becomes conductive.

5. Compare and contrast the behavior of capacitors and inductors in AC circuits.

   1. Capacitors impede AC current while inductors facilitate it; inductors store energy in a magnetic field while capacitors store energy in an electric field
   2. Both impede AC current; both store energy in a magnetic field
   3. Both facilitate AC current; both store energy in an electric field
   4. Capacitors facilitate AC current while inductors impede it; both store energy in an electric field
   Show answer

   Answer: A. Capacitors impede AC current while inductors facilitate it; inductors store energy in a magnetic field while capacitors store energy in an electric field

   Capacitors oppose changes in voltage, leading to impedance of AC current, while inductors oppose changes in current. Capacitors store energy in an electric field, and inductors in a magnetic field.

More questions in this quiz

Answers and explanations are in the full quiz.

1. What is the unit of capacitance?
2. A capacitor has a capacitance of 10 μF. What does this mean?
3. How does the dielectric constant affect the capacitance of a capacitor?
4. Two capacitors of capacitance 2 μF and 3 μF are connected in series. What is the equivalent capacitance?
5. Two capacitors of capacitance 2 μF and 3 μF are connected in parallel. What is the equivalent capacitance?
6. Explain the concept of time constant in an RC circuit.
7. Derive the expression for the energy stored in a parallel plate capacitor.
8. A parallel plate capacitor has a capacitance C. If the area of the plates is doubled and the distance between them is halved, what is the new capacitance?
9. Describe the behavior of a capacitor in a DC circuit after a long time.
10. Derive the expression for the time constant of an RC circuit during charging.
11. Explain how a capacitor can be used to smooth out voltage fluctuations in a power supply.
12. A capacitor is charged using a constant current source. Derive an expression for the voltage across the capacitor as a function of time.
13. Explain the concept of displacement current and its significance in Maxwell's equations.
14. Analyze the transient response of an RC circuit subjected to a step input voltage.

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