# Explain why alpha radiation is more ionising than gamma radiation but is also stopped more easily by materials.

> Eduqas GCSE Physics — 9.2 Absorption and emission of ionising radiations · Explain · 4 marks

## Mark scheme (4 marks)

1. Alpha particles have a large mass and/or charge (doubly charged / charge of +2)
2. The large charge / size of alpha causes it to interact strongly with matter, ionising many atoms in a short distance
3. Because alpha loses energy rapidly through frequent ionisation events, it is stopped quickly / has a short range
4. Gamma radiation has no charge / no mass, so it rarely interacts with atoms and is therefore more penetrating but less ionising

## Key terms

- [alpha radiation](https://www.gradenine.co.uk/glossary/alpha-radiation)
- [gamma radiation](https://www.gradenine.co.uk/glossary/gamma-radiation)
- [ionising](https://www.gradenine.co.uk/glossary/ionising)

## Related

- [Revision notes for Eduqas GCSE Physics](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-why-alpha-radiation-is-more-4785dabd) · Published by Druglandscape Ltd.