# The Sun is described as a black body. Explain what is meant by a black body and describe how the Sun maintains a constant temperature in space.

> Eduqas A-Level Physics — 6.3 Stellar evolution and cosmology (A-Level only) · Explain · 5 marks

## Mark scheme (5 marks)

1. A black body absorbs all radiation that is incident on it
2. A black body is also an ideal emitter of radiation
3. At constant temperature, the Sun radiates the same average power that it absorbs
4. If the Sun absorbs more power than it emits, its temperature would rise
5. If the Sun emits more power than it absorbs, its temperature would fall

## Key terms

- [black body](https://www.gradenine.co.uk/glossary/black-body)
- [constant temperature](https://www.gradenine.co.uk/glossary/constant-temperature)

## Related

- [Revision notes for Eduqas A-Level Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/the-sun-is-described-as-a-d4f6dd79) · Published by Druglandscape Ltd.