# Explain how a loudspeaker uses variations in current to produce sound waves.

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

> A loudspeaker is connected to an audio amplifier. As music plays, the current supplied to the loudspeaker continually changes in size and direction.

## Mark scheme (4 marks)

1. The varying current flows through a coil (in a magnetic field), producing a force on the coil
2. As the current varies (in size and direction), the force on the coil varies, causing the coil to move back and forth
3. The moving coil causes the diaphragm to vibrate
4. The vibrating diaphragm produces corresponding sound waves (in the surrounding air)

## Key terms

- [loudspeaker](https://www.gradenine.co.uk/glossary/loudspeaker)
- [current](https://www.gradenine.co.uk/glossary/current)
- [sound waves](https://www.gradenine.co.uk/glossary/sound-waves)

## 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-loudspeaker-uses-variations-da3996b0) · Published by Druglandscape Ltd.