# The Sun and a distant red giant star both emit electromagnetic radiation. The Sun has a surface temperature of approximately 5500 °C, while the red giant has a surface temperature of approximately 3500 °C. Both stars behave as black bodies. Describe how the intensity and peak wavelength of radiation emitted by the Sun differs from that emitted by the red giant, and explain why these differences occur.

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

## Mark scheme (4 marks)

1. The Sun emits radiation of greater (total) intensity / power per unit area than the red giant
2. The Sun emits radiation at a shorter peak wavelength than the red giant
3. A hotter body emits more intense radiation / more power because it has more energy to radiate
4. A hotter body emits radiation with a shorter peak wavelength / peak wavelength decreases as temperature increases

## Key terms

- [intensity](https://www.gradenine.co.uk/glossary/intensity)
- [peak wavelength](https://www.gradenine.co.uk/glossary/peak-wavelength)
- [temperature](https://www.gradenine.co.uk/glossary/temperature)

## Related

- [Revision notes for Eduqas GCSE Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and 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/the-sun-and-a-distant-red-4c77c4ac) · Published by Druglandscape Ltd.