# A student sets up a circuit containing a battery, a motor, and a lamp connected in series. The motor is used to lift a small weight. Explain how energy is transferred from the battery to the surroundings in this circuit, including the role of potential difference.

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

> The battery has a potential difference of 6 V. The potential difference across the motor is 4 V and the potential difference across the lamp is 2 V.

## Mark scheme (4 marks)

1. The potential difference (voltage) is a measure of the energy transferred per unit charge / work done per unit charge between two points in the circuit.
2. The sum of the potential differences across the motor and the lamp equals the potential difference of the battery / the p.d.s across the components share the total p.d. of the supply (4 V + 2 V = 6 V).
3. Chemical energy in the battery is transferred to electrical energy, which is then transferred to kinetic / mechanical energy by the motor (to lift the weight).
4. The lamp transfers electrical energy to thermal energy (and light energy) / current does work against the resistance of the lamp, producing heat and light.

## Key terms

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

## 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-student-sets-up-a-circuit-ddfbe7d1) · Published by Druglandscape Ltd.