# Radioactive sources emit different types of nuclear radiation. Explain how the properties of alpha, beta and gamma radiation differ in terms of their penetrating power and what materials can stop each type.

> Eduqas A-Level Physics — 6.1 Radioactivity · Explain · 5 marks

> A technician in a nuclear laboratory needs to select the correct shielding material to protect workers from three different radioactive sources. The sources emit alpha particles, beta particles and gamma rays respectively.

## Mark scheme (5 marks)

1. Alpha particles have the least penetrating power / are stopped by a few centimetres of air or a thin sheet of paper
2. Beta particles have intermediate penetrating power / are stopped by a few millimetres of aluminium (or equivalent metal sheet)
3. Gamma rays have the greatest penetrating power / are only reduced (not fully stopped) by thick lead or several centimetres of concrete
4. Alpha particles are the most ionising because they are large / carry a 2+ charge, which explains their low penetrating power
5. Gamma rays are the least ionising because they are electromagnetic waves / have no charge / mass, which explains their high penetrating power

## Key terms

- [penetrating power](https://www.gradenine.co.uk/glossary/penetrating-power)

## Related

- [Revision notes for Eduqas A-Level 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/radioactive-sources-emit-different-types-of-c447f72b) · Published by Druglandscape Ltd.