# A 12 V battery is connected to two resistors in series. One resistor has a potential difference of 4 V across it. Explain how the potential differences are distributed across the two resistors and describe how this distribution would change if the resistors were reconnected in parallel instead.

> Pearson Edexcel International GCSE Physics (4PH1) — 2.2 Energy and voltage in circuits · Explain · 4 marks

> A 12 V battery is connected to two resistors in series. The potential difference across one resistor is measured as 4 V.

## Mark scheme (4 marks)

1. In series, the potential differences across the components add up to the total supply potential difference (12 V), so the second resistor has 8 V across it.
2. In series, the resistor with the higher resistance has a greater potential difference across it.
3. In parallel, both resistors have the same potential difference across them.
4. In parallel, each resistor has the full supply potential difference (12 V) across it, so neither resistor shares the voltage.

## Key terms

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

## Related

- [Revision notes for Pearson Edexcel International GCSE Physics (4PH1)](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-12-v-battery-is-connected-66affdb2) · Published by Druglandscape Ltd.