# A mobile phone uses microwaves to send and receive signals. Explain why engineers designing a new phone are advised to limit the intensity of microwaves that pass through a user's head.

> Edexcel GCSE Physics (1PH0) — 5.1 Light and the electromagnetic spectrum · Explain · 4 marks

> Mobile phones communicate via microwaves, which are part of the electromagnetic spectrum. Regulatory bodies set maximum limits on the power of microwaves that electronic devices are permitted to emit close to the human body.

## Mark scheme (4 marks)

1. Microwaves are absorbed by body cells / tissue
2. This absorption causes internal heating of body cells
3. Higher intensity means more energy is transferred to the cells
4. This can damage body cells / cause harm to the user

## Key terms

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

## 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/a-mobile-phone-uses-microwaves-to-a276e01d) · Published by Druglandscape Ltd.