# A market stall sells oranges under a sodium street lamp that emits only yellow light. Explain what colour the orange skin appears under the yellow light, and explain what colour the orange skin would appear under blue light only.

> Eduqas GCSE Physics — 6.4 Colour and frequency · Explain · 4 marks

## Mark scheme (4 marks)

1. Under yellow light, the orange skin reflects yellow light (because orange surfaces reflect red and yellow wavelengths)
2. So the orange skin appears yellow (under the sodium lamp)
3. Under blue light only, the orange skin absorbs the blue light (because orange skin does not reflect blue wavelengths)
4. So the orange skin appears black (under blue light only)

## Key terms

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

## 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)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-market-stall-sells-oranges-under-a8d2e1a6) · Published by Druglandscape Ltd.