# State and explain two safety precautions a laboratory technician should take when handling a radioactive source, relating each precaution to the properties of ionising radiation.

> Cambridge International IGCSE Physics (0625) — 5.2 Radioactivity · Explain · 4 marks

## Mark scheme (4 marks)

1. Keep source at a distance / use tongs or forceps to handle the source
2. Because count rate decreases with distance / reducing exposure to ionising radiation which can remove electrons from atoms (forming ions) and cause mutations in DNA
3. Use shielding / store the source in a lead-lined container
4. Because shielding absorbs the radiation / gamma rays require several centimetres of lead to stop them, so lead shielding prevents ionising radiation reaching living tissues

## Key terms

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

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](https://www.gradenine.co.uk/learn)
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