Lesson 3.7.5.4

3.7.5.4 Electromagnetic induction Quiz: AQA Physics, Unit 7

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.7.5.4, Electromagnetic induction: 20 multiple choice questions for the AQA Physics (7408), Unit 7: Fields and their consequences (A-level only), written with Revision Ninja.

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The 20 questions

  1. According to Faraday's law, the magnitude of induced electromotive force equals what quantity?

    • Magnetic flux density
    • Magnetic flux linkage
    • Rate of flux change
    • Rate of charge flow

  2. According to Lenz's law, the direction of an induced current always opposes what?

    • The change causing it
    • The initial flux linkage
    • The external magnetic field
    • The induced electromotive force

  3. Which formula gives the magnitude of induced electromotive force in a coil of N turns?

    • ε = N ΔΦ / Δt
    • ε = ΔΦ / (N Δt)
    • ε = N Φ Δt
    • ε = N Δt / ΔΦ

  4. A 200-turn coil has flux changing from 0 to 5.0 x 10^-4 Wb in 0.10 s. What is the average induced emf?

    • 0.10 V
    • 1.0 V
    • 10 V
    • 0.010 V

  5. A straight conductor of length 0.25 m moves at 4.0 m/s perpendicular to a field of 0.20 T. What emf is induced across it?

    • 3.2 V
    • 0.80 V
    • 0.20 V
    • 0.050 V

  6. A 50-turn coil of area 0.020 m^2 rotates uniformly in a field of 0.10 T at angular speed 100 rad/s. What is the peak emf?

    • 100 V
    • 5.0 V
    • 1.0 V
    • 10 V

  7. A 100-turn coil of area 0.02 m^2 in a field of 0.05 T rotates at 50 Hz. What is the peak emf?

    • 157 V
    • 16 V
    • 1.6 V
    • 0.16 V

  8. The flux through a single-turn coil changes uniformly from 0.040 Wb to 0.010 Wb in 0.02 s. What is the induced emf?

    • 1.5 V
    • 0.030 V
    • 0.50 V
    • 3.0 V

  9. When a magnet's north pole approaches a coil, what magnetic pole is induced at that face?

    • North pole
    • Negative pole
    • Positive pole
    • South pole

  10. In what coil orientation relative to a magnetic field is the induced electromotive force maximum?

    • Parallel to field
    • Stationary at rest
    • At 45 degrees
    • Perpendicular to field

  11. A 0.50 m rod moves at 2.0 m/s across a field of 0.40 T and is part of a 25 ohm circuit. What current flows?

    • 16 mA
    • 1.6 mA
    • 160 mA
    • 0.40 A

  12. Which conservation law requires that an induced current must oppose the change producing it?

    • Conservation of charge
    • Newton's third law
    • Conservation of energy
    • Conservation of momentum

  13. A 400-turn coil has flux falling from 3.0 mWb to zero in 0.25 s. What is the average emf?

    • 0.0030 V
    • 4.8 V
    • 1.2 V
    • 0.48 V

  14. A 100-turn coil of area 0.0050 m^2 in a field of 0.40 T turns from normal alignment to parallel in 0.020 s. What is the average emf?

    • 20 V
    • 0.20 V
    • 5.0 V
    • 10 V

  15. A 0.30 m rod moves at 1.5 m/s across a field of 0.25 T. What emf is developed across its ends?

    • 0.11 V
    • 0.045 V
    • 1.1 V
    • 0.75 V

  16. A 100-turn coil has an induced emf of 2.0 V. What is the rate of change of flux?

    • 0.020 Wb/s
    • 2.0 Wb/s
    • 200 Wb/s
    • 0.0020 Wb/s

  17. A loop of area 0.030 m^2 lies normal to a field that changes at 0.50 T/s. What emf is induced?

    • 1.5 V
    • 0.015 V
    • 0.0015 V
    • 0.15 V

  18. If the rate of change of flux linkage in a coil doubles, what happens to induced emf?

    • It quadruples
    • It halves
    • It doubles
    • It remains constant

  19. A 40-turn coil has a constant induced emf of 0.60 V. What is the rate of change of flux?

    • 0.015 Wb/s
    • 0.15 Wb/s
    • 1.5 Wb/s
    • 0.024 Wb/s

  20. A flat coil rotates with angular speed omega in a uniform field. If omega is doubled with N, B and A unchanged, what happens to the peak emf?

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

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