# Explain how a microphone converts sound waves into an electrical current.

> Edexcel GCSE Physics (1PH0) — 13.1 Electromagnetic induction (Phys only) · Explain · 4 marks

> A singer performs into a microphone on stage. The microphone is connected to an amplifier so the sound can be heard throughout the venue.

## Mark scheme (4 marks)

1. Pressure variations in sound waves cause the coil (inside the microphone) to move
2. The coil moves relative to (through) the magnetic field / relative motion exists between the coil and the magnet
3. A potential difference is induced across the ends of the coil (generator effect)
4. The induced current varies in proportion to the pressure variations of the sound waves, so the electrical signal matches the sound signal

## Key terms

- [microphone](https://www.gradenine.co.uk/glossary/microphone)

## Related

- [Revision notes for Edexcel GCSE Physics (1PH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-a-microphone-converts-sound-066b4504) · Published by Druglandscape Ltd.