Lesson 3.5.1.6

3.5.1.6 Electromotive force and internal resistance Quiz: AQA Physics, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.5.1.6, Electromotive force and internal resistance: 20 multiple choice questions for the AQA Physics (7408), Unit 5: Electricity, written with Revision Ninja.

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The 20 questions

  1. What is the electromotive force (emf) of an electrical power supply defined as?

    • Energy per unit charge
    • Work per unit current
    • Power per unit charge
    • Charge per unit energy

  2. What is the mathematical expression for the terminal potential difference V of a cell?

    • I r - E
    • E / I r
    • E + I r
    • E - I r

  3. The emf equation for a complete circuit is:

    • E = I / (R + r)
    • E = I R
    • E = I(R + r)
    • E = (R + r) / I

  4. On a graph of terminal potential difference against current, what does the gradient represent?

    • E
    • +r
    • -E
    • -r

  5. The y-intercept of a graph of terminal pd against current, at zero current, gives:

    • the external resistance
    • the short-circuit current
    • the internal resistance
    • the emf

  6. When external circuit resistance is much larger than internal resistance, terminal voltage is approximately equal to what?

    • Lost volts
    • Electromotive force
    • Zero volts
    • Short circuit current

  7. The short-circuit current of a cell with emf E and internal resistance r is:

    • E / r
    • E x r
    • E + r
    • E / (R + r)

  8. A 1.5 V cell with internal resistance 0.50 ohm is connected to a 2.5 ohm resistor. What is the terminal pd?

    • 1.5 V
    • 2.0 V
    • 1.25 V
    • 0.75 V

  9. A 1.5 V cell with internal resistance 0.50 ohm is connected to a 2.5 ohm resistor. What is the current?

    • 0.50 A
    • 0.60 A
    • 3.0 A
    • 1.5 A

  10. A battery has emf 12 V and internal resistance 0.40 ohm. What is its short-circuit current?

    • 12.4 A
    • 30 A
    • 3.0 A
    • 4.8 A

  11. A 6.0 V cell with internal resistance 2.0 ohm drives a current through a 10 ohm external resistor. What is the lost volts?

    • 1.0 V
    • 2.0 V
    • 5.0 V
    • 0.5 V

  12. Measurements on a cell give terminal pd 8.4 V at 0.50 A and 7.8 V at 1.0 A. What is the emf?

    • 8.4 V
    • 9.0 V
    • 7.8 V
    • 10.2 V

  13. The terminal pd of a cell is 9.0 V with no current and falls to 7.5 V at a current of 2.0 A. What is the internal resistance?

    • 0.75 ohm
    • 4.5 ohm
    • 1.5 ohm
    • 0.13 ohm

  14. A 12 V cell supplies a steady 2.0 A for 10 minutes. What total energy is transferred by the cell?

    • 14.4 kJ
    • 1.44 kJ
    • 7.2 kJ
    • 144 kJ

  15. What variables plotted on y-axis and x-axis yield a straight line to find cell emf?

    • Current against terminal pd
    • Terminal pd against current
    • Emf against resistance
    • Resistance against current

  16. A 1.5 V cell with internal resistance 1.0 ohm drives a 2.0 ohm external resistor. What power is dissipated in the external resistor?

    • 0.25 W
    • 0.50 W
    • 1.0 W
    • 0.75 W

  17. Two identical 1.5 V cells, each with internal resistance 0.20 ohm, are in series with a 2.6 ohm resistor. What is the current?

    • 0.5 A
    • 3.0 A
    • 1.2 A
    • 1.0 A

  18. Two identical cells, each 1.5 V with internal resistance 0.60 ohm, are in parallel with a 2.4 ohm resistor. What is the current?

    • 1.0 A
    • 0.63 A
    • 0.56 A
    • 0.25 A

  19. When is the terminal potential difference of a power supply exactly equal to its electromotive force?

    • Zero current flowing
    • Maximum current flowing
    • Resistance equals zero
    • Circuit switch closed

  20. A 12 V cell with internal resistance 0.50 ohm drives a 5.5 ohm lamp. What power does the lamp dissipate?

    • 22 W
    • 44 W
    • 2.0 W
    • 11 W

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