# A copper wire and a longer copper wire of the same thickness are each connected separately to identical batteries. Explain why the longer wire has a greater resistance and describe the effect this greater resistance has on the current flowing through it.

> OCR A-Level Physics A (H556) — 3.4 Materials · Explain · 5 marks

> Copper is a conductor commonly used in electrical circuits. The resistance of a wire depends on several factors, including its length.

## Mark scheme (5 marks)

1. Electrons (charge) flow through the wire and collide with atoms in the wire
2. The longer wire has more atoms for electrons to collide with / electrons must travel through more atoms
3. More collisions make it harder for electrons to flow, so resistance increases with length
4. Greater resistance means the current is lower / the current decreases as resistance increases
5. The same potential difference (voltage) now has to push the current through a greater resistance, which is why the current is reduced (owtte — linking p.d., resistance and current correctly)

## Key terms

- [resistance](https://www.gradenine.co.uk/glossary/resistance)

## Related

- [Revision notes for OCR A-Level Physics A (H556)](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-copper-wire-and-a-longer-974fca92) · Published by Druglandscape Ltd.