Lesson 4.7.3.3

4.7.3.3 Microphones (HT only) Quiz: AQA Physics, Unit 7

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.7.3.3, Microphones (HT only): 20 multiple choice questions for the AQA GCSE Physics (8463), Unit 7: Magnetism and electromagnetism, written with Revision Ninja.

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The 20 questions

  1. Which effect does a moving-coil microphone use to turn sound into an electrical signal?

    • The photoelectric effect
    • Thermionic emission
    • The motor effect
    • The generator effect

  2. What is the primary job of the diaphragm in a moving-coil microphone?

    • Amplify the sound
    • Block the sound
    • Generate voltage directly
    • Move the coil

  3. What do sound pressure variations become inside a moving-coil microphone?

    • Magnetic variations
    • Current variations
    • Resistance variations
    • Temperature variations

  4. In a moving-coil microphone, through which region must the coil move?

    • Magnetic field
    • Electric field
    • Gravitational field
    • Vacuum chamber

  5. How does the coil move inside a working microphone?

    • In circles
    • Stays stationary
    • Back and forth
    • Only outwards

  6. What type of current is typically produced by a moving-coil microphone?

    • Direct current
    • Alternating current
    • Pulsed current
    • Static current

  7. What name is given to a current produced by a changing magnetic field in a coil?

    • Thermal current
    • Induced current
    • Resistive current
    • Static current

  8. What phenomenon inside a microphone induces a current in the coil?

    • Thermal expansion
    • Electrostatic charging
    • Magnetic flux changes
    • Chemical reactions

  9. A microphone coil oscillates at 200 Hz. What is the frequency of the alternating current it produces?

    • 50 Hz
    • 200 Hz
    • 400 Hz
    • 100 Hz

  10. A diaphragm moves forward and back 500 times each second. How many complete cycles does the output current have per second?

    • 1000
    • 50
    • 250
    • 500

  11. What happens to the induced current when a louder sound makes the coil move faster?

    • It remains unchanged
    • It becomes larger
    • It drops to zero
    • It reverses frequency

  12. Which graph best represents the output current against time for a steady tone?

    • Sine wave
    • Straight horizontal line
    • Steep vertical line
    • Exponential decay curve

  13. What determines the frequency of a microphone's electrical output signal?

    • Circuit resistance
    • Magnet strength
    • Coil mass
    • Sound wave frequency

  14. What happens to the induced potential difference if the magnetic field is weaker?

    • It reverses direction
    • It stays unchanged
    • It decreases
    • It increases

  15. How does doubling the number of turns on the coil affect the induced p.d.?

    • Remains the same
    • Halved in size
    • Twice as large
    • Four times larger

  16. What primary energy transfer occurs in a moving-coil microphone?

    • Electrical to thermal
    • Potential to chemical
    • Chemical to kinetic
    • Kinetic to electrical

  17. Why does a moving-coil microphone output an alternating signal rather than a steady one?

    • Diaphragm melting
    • Battery power reversal
    • Oscillating coil motion
    • Commutator ring action

  18. For the same sound, what happens if a stiffer microphone diaphragm is fitted?

    • Current becomes direct
    • Frequency doubles
    • Induced p.d. increases
    • Induced p.d. decreases

  19. What supplies the energy that produces the electrical signal in a microphone?

    • An internal battery
    • Thermal radiation
    • The sound wave
    • The magnetic field

  20. What factor does NOT alter the induced p.d. in a moving-coil microphone?

    • Number of turns
    • Coil speed
    • Field strength
    • Case colour

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