# A student connects a battery to a resistor in a circuit. Explain the difference between the electromotive force (e.m.f.) of the battery and the potential difference across the resistor.

> Cambridge International IGCSE Physics (0625) — 4.2 Electrical quantities · Explain · 4 marks

## Mark scheme (4 marks)

1. E.m.f. is the electrical work done by the battery / power source in moving a unit charge around the complete circuit
2. Potential difference is the work done by a unit charge passing through a component / the energy transferred from electrical energy by unit charge in the resistor
3. E.m.f. refers to energy given to charges by the source / input of energy, whereas potential difference refers to energy transferred away by / released in a component
4. Both e.m.f. and potential difference are measured in volts (V)

## Key terms

- [electromotive force](https://www.gradenine.co.uk/glossary/electromotive-force)
- [potential difference](https://www.gradenine.co.uk/glossary/potential-difference)

## 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/a-student-connects-a-battery-to-a255bc42) · Published by Druglandscape Ltd.