# A student claims that a black body radiator emits only visible light. Explain why this claim is incorrect, and describe how the peak wavelength of radiation emitted by a black body changes as its temperature increases.

> Eduqas GCSE Physics — 6.5 Black body radiation · Explain · 4 marks

> A black body is a perfect absorber and emitter of all wavelengths of electromagnetic radiation. The wavelength at which most radiation is emitted depends on the temperature of the object.

## Mark scheme (4 marks)

1. A black body emits radiation across all/a range of wavelengths (not just visible light)
2. The peak wavelength decreases as temperature increases
3. At lower temperatures, the peak wavelength is in the infrared region
4. At higher temperatures, the peak wavelength shifts into the visible region (e.g. red, then white/blue-white light)

## Key terms

- [black body radiator](https://www.gradenine.co.uk/glossary/black-body-radiator)
- [peak wavelength](https://www.gradenine.co.uk/glossary/peak-wavelength)

## Related

- [Revision notes for Eduqas GCSE Physics](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-student-claims-that-a-black-cad62d6a) · Published by Druglandscape Ltd.