# A student observes that a solar cell produces a larger electric current when bright sunlight shines on it compared to dim sunlight of the same colour. The student also notices that when red light shines on the solar cell, fewer electrons are released than when blue light of the same brightness shines on it. Explain both of these observations in terms of photons.

> Eduqas A-Level Physics — 2.7 Photons · Explain · 5 marks

> Solar cells release electrons when light falls on them. The number of electrons released and the energy each electron receives depends on the nature of the light used.

## Mark scheme (5 marks)

1. Light consists of photons (discrete packets/quanta of energy)
2. Brighter light of the same colour means more photons arriving per second
3. More photons means more electrons are released per second, so a larger current is produced
4. The energy of a photon depends on its frequency / blue light has a higher frequency than red light
5. Blue photons have enough energy to release electrons (more easily / in greater numbers) whereas red photons have less energy so fewer electrons are released

## Key terms

- [photon](https://www.gradenine.co.uk/glossary/photon)
- [current](https://www.gradenine.co.uk/glossary/current)

## 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)
- [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-observes-that-a-solar-11bf6278) · Published by Druglandscape Ltd.