Lesson 7.3.1

7.3.1 Capacitance and energy stored in a capacitor Quiz: Pearson Edexcel Physics, Unit 7

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 7.3.1, Capacitance and energy stored in a capacitor: 20 multiple choice questions for the Pearson Edexcel Physics (9PH0), Unit 7: Electric and Magnetic Fields, written with Revision Ninja.

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The 20 questions

  1. How is electrical capacitance defined mathematically?

    • Current per unit voltage
    • Charge per unit voltage
    • Energy per unit charge
    • Voltage per unit charge

  2. What is the SI unit of capacitance?

    • Farad
    • Coulomb
    • Volt
    • Ohm

  3. Which expression gives the energy stored in a capacitor of capacitance C when the potential difference across it is V?

    • W = (1/2) C V^2
    • W = C V / 2
    • W = C V^2
    • W = 2 C V^2

  4. What does the area under a potential difference against charge graph represent?

    • Energy stored
    • Current
    • Capacitance
    • Power

  5. What is the gradient of a graph of potential difference V against charge Q for a capacitor?

    • 1/C
    • 1/2 C
    • C^2
    • C

  6. A 100 microfarad capacitor is charged to 12 V. What charge is stored on it?

    • 1.2 x 10^-5 C
    • 1.2 x 10^-3 C
    • 8.3 x 10^-6 C
    • 0.12 C

  7. A 4.7 millifarad capacitor is charged to 9.0 V. How much energy is stored?

    • 0.19 J
    • 1.9 J
    • 0.38 J
    • 0.042 J

  8. A 2.0 microfarad capacitor is charged to 200 V. What energy is stored in it?

    • 0.00020 J
    • 0.40 J
    • 0.040 J
    • 0.020 J

  9. A capacitor stores 0.50 J of energy when the potential difference across it is 10 V. What is its capacitance?

    • 5.0 mF
    • 10 mF
    • 0.10 F
    • 20 mF

  10. A capacitor stores 3.0 millicoulomb of charge at a potential difference of 6.0 V. How much energy is stored?

    • 2.0 x 10^-3 J
    • 9.0 x 10^-3 J
    • 4.5 x 10^-3 J
    • 1.8 x 10^-2 J

  11. If the potential difference across a capacitor is doubled, by what factor does stored energy change?

    • 16
    • 4
    • 2
    • 8

  12. A 470 microfarad capacitor stores 0.40 J of energy. What is the potential difference across it?

    • 0.85 V
    • 41 V
    • 0.0017 V
    • 1700 V

  13. A capacitor is charged so that its V against Q graph passes through the point (2.0 mC, 10 V). What is the energy stored?

    • 0.020 J
    • 0.20 J
    • 0.0050 J
    • 0.010 J

  14. A capacitor of fixed capacitance has its potential difference doubled. What happens to the charge stored on it?

    • It doubles
    • It halves
    • It quadruples
    • It is unchanged

  15. A 5.0 microfarad capacitor stores 2.5 millijoule of energy. What charge is stored on it?

    • 6.3 x 10^-4 C
    • 1.6 x 10^-4 C
    • 1.6 x 10^-3 C
    • 3.2 x 10^-4 C

  16. A 1.0 microfarad capacitor is charged to 10 V and then the potential difference across it is reduced to 6.0 V. How much energy is lost from the capacitor?

    • 3.2 x 10^-5 J
    • 1.8 x 10^-5 J
    • 5.0 x 10^-5 J
    • 6.8 x 10^-5 J

  17. A 4.0 microfarad capacitor and a separate 2.0 microfarad capacitor are each charged to 10 V. What is the total energy stored in both?

    • 1.5 x 10^-4 J
    • 2.0 x 10^-4 J
    • 3.0 x 10^-4 J
    • 6.0 x 10^-4 J

  18. On a graph of potential difference against charge, what quantity represents the energy stored in a capacitor?

    • Maximum charge stored
    • Peak potential difference
    • Gradient of graph
    • Area under graph

  19. Which equation correctly calculates the energy W stored in a capacitor?

    • C V^2
    • C / V^2
    • (1/2) C V^2
    • (1/2) C^2 V

  20. A capacitor stores 6.0 millicoulomb of charge at a potential difference of 3.0 V. What is its capacitance?

    • 2.0 mF
    • 0.50 mF
    • 0.20 F
    • 18 mF

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