# A convex lens can be used to form a real image of a distant object. Explain how a convex lens brings parallel rays of light to a focus, and state what is meant by the term 'focal length'.

> WJEC GCSE Physics (Wales) — 2.1 Light, lenses and the universe · Explain · 4 marks

## Mark scheme (4 marks)

1. Parallel rays of light are refracted (bent) as they enter and leave the convex lens
2. The rays are bent towards the principal axis / converge after passing through the lens
3. The rays meet at a single point called the focal point (principal focus)
4. The focal length is the distance from the centre of the lens to the focal point (principal focus)

## Key terms

- [convex lens](https://www.gradenine.co.uk/glossary/convex-lens)
- [focal length](https://www.gradenine.co.uk/glossary/focal-length)
- [parallel rays](https://www.gradenine.co.uk/glossary/parallel-rays)

## Related

- [Revision notes for WJEC GCSE Physics (Wales)](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-convex-lens-can-be-used-a8c7b9f1) · Published by Druglandscape Ltd.