# A technician is storing radioactive sources in a laboratory. One source emits alpha radiation, one emits beta radiation, and one emits gamma radiation. Describe the nature of each type of radiation and explain which source poses the greatest risk to a worker who accidentally swallows a source.

> AQA A-Level Physics (7408) — 3.8.1 Radioactivity · Describe and Explain · 5 marks

## Mark scheme (5 marks)

1. Alpha radiation consists of a helium nucleus (two protons and two neutrons)
2. Beta radiation is a fast-moving electron (emitted from the nucleus)
3. Gamma radiation is electromagnetic radiation / a wave (not a particle)
4. The alpha source poses the greatest risk when swallowed / inside the body
5. Because alpha radiation is the most ionising / causes the most ionisation of body tissue, and cannot escape the body (is absorbed by surrounding tissue)

## Key terms

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

## Related

- [Revision notes for AQA A-Level Physics (7408)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and 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-technician-is-storing-radioactive-sources-7f026022) · Published by Druglandscape Ltd.