# Explain how a microphone converts sound into a varying electrical current.

> WJEC GCSE Physics (Wales) — 1.9 Electromagnetism · Explain · 4 marks

> A microphone is used to pick up a singer's voice during a live performance. The microphone is connected to a recording device.

## Mark scheme (4 marks)

1. Sound waves cause pressure variations that make the diaphragm vibrate
2. A coil of wire is attached to the diaphragm and moves with it inside a magnetic field
3. The generator effect causes a potential difference to be induced across the coil
4. The induced current varies in the same way as the pressure variations in the sound, producing a corresponding current variation

## Key terms

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

## Related

- [Revision notes for WJEC GCSE Physics (Wales)](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-ecf99908) · Published by Druglandscape Ltd.