# State and explain how the orbital speed and surface temperature of a planet are each related to its distance from the Sun.

> Cambridge International IGCSE Physics (0625) — 6.1 Earth and the Solar System · Explain · 4 marks

## Mark scheme (4 marks)

1. Orbital speed decreases as distance from the Sun increases
2. Because the Sun's gravitational field strength decreases with distance, so there is less force pulling the planet along its orbit
3. Surface temperature decreases as distance from the Sun increases
4. Because planets further from the Sun receive less radiation / energy per unit area from the Sun

## Key terms

- [orbital speed](https://www.gradenine.co.uk/glossary/orbital-speed)
- [surface temperature](https://www.gradenine.co.uk/glossary/surface-temperature)

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](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/state-and-explain-how-the-orbital-a5716503) · Published by Druglandscape Ltd.