# Explain what happens to the speed, wavelength, and direction of a monochromatic ray of light as it passes from glass into air.

> AQA A-Level Physics (7408) — 3.3.2 Refraction, Diffraction and Interference · Explain · 5 marks

> A ray of monochromatic light travels from glass into air, crossing the boundary between the two materials.

## Mark scheme (5 marks)

1. The speed of light increases as it moves from glass into air
2. The wavelength increases as the light enters air
3. The frequency remains unchanged / stays constant
4. The ray bends away from the normal as it enters the less dense material
5. Air is less dense than glass, so the ray changes direction because the wave speeds up at the boundary

## Key terms

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

## Related

- [Revision notes for AQA A-Level Physics (7408)](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/explain-what-happens-to-the-speed-14e961bf) · Published by Druglandscape Ltd.