# A surgeon uses a laser to perform a delicate eye operation. Explain why laser light is more suitable than ordinary white light from a lamp for this medical procedure.

> WJEC A-Level Physics (Wales) — 2.8 Lasers · Explain · 5 marks

> Lasers are used in medicine for many precise surgical procedures, including correcting problems with vision.

## Mark scheme (5 marks)

1. Laser light is monochromatic (one wavelength/colour) so the energy delivered to the tissue is precisely controlled
2. Laser light is coherent, meaning all waves are in phase with each other
3. Laser light is emitted as a very narrow, parallel beam (highly collimated) that does not spread out
4. The narrow beam means energy can be directed at a very small, precise area of the eye without affecting surrounding tissue
5. Ordinary white light from a lamp spreads out in all directions and contains many wavelengths, making it impossible to direct precisely enough for surgery

## Key terms

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

## Related

- [Revision notes for WJEC A-Level 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-surgeon-uses-a-laser-to-8442b02a) · Published by Druglandscape Ltd.