# A student charges a capacitor using a 6 V battery. The capacitor stores a charge of 12 μC. The student then replaces the battery with a 12 V battery and charges the same capacitor fully. Explain how the capacitance, charge stored, and energy stored change when the higher voltage battery is used.

> AQA A-Level Physics (7408) — 3.7.4 Capacitance · Explain · 5 marks

## Mark scheme (5 marks)

1. Capacitance does not change / remains the same
2. Charge stored doubles (to 24 μC) because charge is proportional to potential difference
3. Correct reasoning linking charge increase to the definition Q = CV with C constant
4. Energy stored increases
5. Energy stored quadruples / increases by a factor of four because energy is proportional to V²

## Key terms

- [capacitance](https://www.gradenine.co.uk/glossary/capacitance)
- [charge](https://www.gradenine.co.uk/glossary/charge)
- [energy stored](https://www.gradenine.co.uk/glossary/energy-stored)

## Related

- [Revision notes for AQA A-Level Physics (7408)](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-charges-a-capacitor-using-2d9a45cd) · Published by Druglandscape Ltd.