# Describe what happens to a light wave when it travels from air into glass, in terms of its speed, wavelength, frequency, and direction of travel.

> OCR GCSE Physics A: Gateway Science (J249) — P4.1 Wave behaviour · Describe · 4 marks

> A physicist is investigating how light behaves when it crosses the boundary between air and a glass block. The light ray strikes the glass surface at an angle.

## Mark scheme (4 marks)

1. The speed of the light wave decreases when it enters the glass
2. The wavelength decreases when the light enters the glass
3. The frequency remains unchanged / stays the same
4. The direction of travel changes / the ray bends towards the normal (as it enters a denser medium)

## Key terms

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

## Related

- [Revision notes for OCR GCSE Physics A: Gateway Science (J249)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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/describe-what-happens-to-a-light-eb371ed0) · Published by Druglandscape Ltd.