# A student has a battery connected to a single resistor in a series circuit. The student then adds a second identical resistor in series with the first. Explain what happens to the potential difference across the original resistor and the current in the circuit after the second resistor is added.

> AQA A-Level Physics (7408) — 3.5.1 Current Electricity · Explain · 5 marks

## Mark scheme (5 marks)

1. Total resistance of the circuit increases
2. Current in the circuit decreases
3. Correct reasoning linking increased resistance to decreased current (e.g. greater resistance opposes current flow more / V = IR so for fixed V, greater R means smaller I)
4. The potential difference of the supply is shared between / split across both resistors
5. The potential difference across the original resistor is less than before / is half the supply voltage (because the resistors are identical)

## Key terms

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

## Related

- [Revision notes for AQA A-Level Physics (7408)](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-has-a-battery-connected-ed1164fe) · Published by Druglandscape Ltd.