# Explain why a perfect black body is considered an ideal emitter as well as an ideal absorber of radiation.

> AQA GCSE Physics (8463) — 4.6.3 Black body radiation (Phys only) · Explain · 4 marks

> All objects absorb and emit radiation. Scientists use the concept of a perfect black body as a theoretical model to understand how objects emit and absorb radiation.

## Mark scheme (4 marks)

1. A perfect black body absorbs all radiation incident on it
2. A perfect black body emits radiation across all wavelengths / emits the maximum possible radiation for its temperature
3. The hotter the object, the greater the amount of infrared radiation emitted in a given time
4. A body remains at a constant temperature when it absorbs radiation at the same rate that it emits it

## Key terms

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

## Related

- [Revision notes for AQA GCSE Physics (8463)](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/explain-why-a-perfect-black-body-63ff1ff1) · Published by Druglandscape Ltd.