# Explain why gamma radiation is the most penetrating type of ionising radiation but is also the least ionising.

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

> The three main types of ionising radiation — alpha, beta, and gamma — differ in their ability to penetrate materials and to ionise atoms along their path.

## Mark scheme (4 marks)

1. Gamma radiation has no charge (or is electromagnetic radiation / a photon)
2. Because it has no charge, it does not interact strongly with / is not easily deflected by atoms in a material, so it can travel far through materials
3. Gamma radiation produces very few ions per unit distance / interacts rarely with atoms along its path
4. Alpha (and beta) particles carry charge, so they interact more strongly with atoms, lose energy quickly and cause many more ionisations (linking greater ionisation to quicker energy loss / shorter range)

## Key terms

- [gamma radiation](https://www.gradenine.co.uk/glossary/gamma-radiation)
- [ionising radiation](https://www.gradenine.co.uk/glossary/ionising-radiation)
- [penetrating](https://www.gradenine.co.uk/glossary/penetrating)
- [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-gamma-radiation-is-the-c44a55a7) · Published by Druglandscape Ltd.