# A security system at an art gallery uses infrared sensors to detect intruders in the dark. Explain why infrared radiation is suitable for this purpose, and describe one other use of infrared radiation in everyday life.

> OCR GCSE Physics A: Gateway Science (J249) — P4.2 The electromagnetic spectrum · Explain · 4 marks

> Art galleries often need to protect valuable paintings overnight without using visible light, which could damage the artworks. Security engineers install sensors that detect radiation emitted by warm objects.

## Mark scheme (4 marks)

1. All objects (above absolute zero) emit infrared radiation
2. Infrared radiation can be detected in the absence of visible light / the sensor detects infrared without needing the room to be lit
3. A named everyday use of infrared radiation
4. Correct description of how infrared is used in that named application

## Key terms

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

## Related

- [Revision notes for OCR GCSE Physics A: Gateway Science (J249)](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/a-security-system-at-an-art-706d94ee) · Published by Druglandscape Ltd.