# A student connects a battery to a resistor and measures the potential difference across the resistor and the current through it. State what is meant by 'potential difference' and explain why the voltmeter must be connected in parallel with the resistor rather than in series.

> Cambridge International IGCSE Physics (0625) — 4.3 Electric circuits · State and Explain · 4 marks

## Mark scheme (4 marks)

1. Potential difference is the work done per unit charge passing through the resistor / component
2. Measured in volts (V)
3. A voltmeter connected in series would change / reduce the current in the circuit because it would add resistance to the circuit
4. A voltmeter in parallel allows it to measure the p.d. across the resistor without significantly affecting the current through the resistor / circuit

## Key terms

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

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](https://www.gradenine.co.uk/learn)
- [How to answer "State 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/a-student-connects-a-battery-to-eea00528) · Published by Druglandscape Ltd.