# Explain why white light separates into different colours when it passes through a glass prism.

> Cambridge International IGCSE Physics (0625) — 3.2 Light · Explain · 4 marks

> A glass prism is used to produce a spectrum from a beam of white light. The colours emerge from the prism spread out, with violet light deviated the most and red light deviated the least.

## Mark scheme (4 marks)

1. White light is made up of different colours / frequencies / wavelengths
2. Different colours travel at different speeds in glass
3. Each colour refracts by a different amount because of its different speed in glass
4. Violet light refracts the most because it travels slowest in glass / has the greatest refractive index; red light refracts the least

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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