# A student connects two resistors in a parallel circuit. The student then reconnects the same two resistors in a series circuit using the same power supply. Explain how the total resistance of the circuit and the current drawn from the power supply differ between the parallel arrangement and the series arrangement.

> OCR A-Level Physics B: Advancing Physics (H557) — 3.2 Forces in action · Explain · 5 marks

> The two resistors each have a resistance of 6 Ω and the power supply has a fixed potential difference.

## Mark scheme (5 marks)

1. In a series circuit the total resistance is the sum of the individual resistances, so total resistance is greater than either individual resistance alone.
2. In a parallel circuit the total resistance is less than the smallest individual resistance.
3. Therefore the total resistance in the parallel arrangement is lower than in the series arrangement.
4. Since the potential difference is the same, a lower resistance means a greater current is drawn from the supply in the parallel circuit (compared to the series circuit).
5. In the parallel circuit, charge has more than one branch/path to flow through, so only some of the charge flows through each branch, reducing the overall resistance experienced.

## Key terms

- [total resistance](https://www.gradenine.co.uk/glossary/total-resistance)
- [parallel](https://www.gradenine.co.uk/glossary/parallel)
- [series](https://www.gradenine.co.uk/glossary/series)
- [current](https://www.gradenine.co.uk/glossary/current)

## Related

- [Revision notes for OCR A-Level Physics B: Advancing Physics (H557)](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-two-resistors-in-5b72d1ee) · Published by Druglandscape Ltd.