Lesson 4.2.2

4.2.2 E.m.f. and p.d. Quiz: OCR Physics, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.2.2, E.m.f. and p.d.: 20 multiple choice questions for the OCR Physics (H156), Unit 3: Electrons, waves and photons, written with Revision Ninja.

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The 20 questions

  1. The unit of potential difference, the volt, is equal to:

    • 1 C J^-1
    • 1 A Ohm
    • 1 J s^-1
    • 1 J C^-1

  2. Which quantity is defined as energy converted to electrical form per coulomb of charge?

    • Electromotive force
    • Electrical resistance
    • Potential difference
    • Electric current

  3. Which quantity is defined as electrical energy converted to other forms per coulomb of charge?

    • Internal resistance
    • Potential difference
    • Electromotive force
    • Electric current

  4. Which energy transfer direction characterizes potential difference across a circuit component?

    • Non-electrical to electrical
    • Chemical to electrical
    • Electrical to non-electrical
    • Mechanical to electrical

  5. The energy transferred to charge Q by a potential difference V is:

    • W = V Q
    • W = Q / V
    • W = V^2 Q
    • W = V / Q

  6. An electron accelerated through a potential difference V gains kinetic energy equal to:

    • V/e
    • e V^2
    • m v^2 / V
    • eV

  7. What does terminal potential difference equal when a cell delivers zero current?

    • Electromotive force
    • Zero volts
    • Internal resistance
    • Lost volts

  8. A cell transfers 6 J of energy to 4 C of charge. What is the e.m.f. of the cell?

    • 0.67 V
    • 10 V
    • 24 V
    • 1.5 V

  9. A 12 V supply moves 0.5 C of charge through a circuit. How much energy is transferred?

    • 6 J
    • 0.04 J
    • 24 J
    • 12.5 J

  10. An electron is accelerated through a potential difference of 200 V. How much energy does it gain?

    • 3.2 x 10^-19 J
    • 1.25 x 10^-21 J
    • 3.2 x 10^-17 J
    • 2.0 x 10^2 J

  11. An electron starts from rest and is accelerated through 100 V. Its speed is closest to:

    • 1.9 x 10^6 m s^-1
    • 5.9 x 10^6 m s^-1
    • 2.0 x 10^4 m s^-1
    • 1.4 x 10^9 m s^-1

  12. A cell with e.m.f. 1.5 V passes 0.2 C of charge through it. How much energy is supplied?

    • 7.5 J
    • 1.7 J
    • 0.13 J
    • 0.3 J

  13. A component with a p.d. of 2.0 V passes 30 C of charge. How much energy is transferred to it?

    • 0.07 J
    • 60 J
    • 32 J
    • 15 J

  14. Two 1.5 V cells are connected in series. What is the total e.m.f.?

    • 3.0 V
    • 0.75 V
    • 1.5 V
    • 4.5 V

  15. A battery transfers 180 J of energy to a total charge of 30 C. What is its e.m.f.?

    • 0.17 V
    • 6 V
    • 5400 V
    • 30 V

  16. A source with e.m.f. 9 V has terminal p.d. 7.5 V when current flows. How much energy per coulomb is lost inside the source?

    • 7.5 J C^-1
    • 16.5 J C^-1
    • 1.5 J C^-1
    • 9 J C^-1

  17. Electromotive force measures energy transferred per unit of which quantity?

    • Time
    • Resistance
    • Current
    • Charge

  18. A 12 V cell supplies a current of 2 A through a lamp for 30 s. How much energy is transferred to the lamp?

    • 360 J
    • 720 J
    • 60 J
    • 1440 J

  19. A 3 V resistor has 50 C of charge passing through it. How much energy is transferred to the resistor?

    • 150 J
    • 53 J
    • 16.7 J
    • 3 J

  20. Which particle gains the most kinetic energy when accelerated across the same potential difference?

    • Alpha particle
    • Proton
    • Positron
    • Electron

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