# Explain why gamma radiation is used to sterilise medical equipment rather than alpha or beta radiation.

> Edexcel GCSE Physics (1PH0) — 6.1 Radioactivity · Explain · 4 marks

> Hospitals use radioactive sources to sterilise surgical instruments. The radiation must be able to penetrate the sealed packaging surrounding the instruments and kill microbes on the surfaces inside.

## Mark scheme (4 marks)

1. Gamma radiation is highly penetrating
2. So gamma can pass through the sealed packaging to reach the instruments inside
3. Alpha radiation is weakly penetrating / stopped by a few centimetres of air or thin materials
4. Beta radiation has only medium penetration / would not reliably penetrate thick packaging as effectively as gamma

## 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)
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