# A student builds a circuit containing a battery, a switch, an ammeter, and three identical lamps. She first connects all three lamps in series. She then rebuilds the circuit so that all three lamps are connected in parallel. Describe and explain the differences the student would observe in the brightness of the lamps and the reading on the ammeter when comparing the parallel circuit to the series circuit.

> Eduqas A-Level Physics — 2.2 DC circuits · Describe and explain · 5 marks

## Mark scheme (5 marks)

1. In the parallel circuit, each lamp is brighter than in the series circuit (or lamps in series are dimmer than in parallel).
2. In a series circuit the same (smaller) current passes through all three lamps, whereas in a parallel circuit each lamp receives the full supply voltage / a greater voltage across each lamp.
3. A greater voltage across each lamp means a greater current through each lamp, so each lamp is brighter.
4. The ammeter reading is higher in the parallel circuit than in the series circuit.
5. In the parallel circuit, each branch carries its own current and these branch currents add together to give a larger total current from the battery.

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and 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-builds-a-circuit-containing-95bbd6ed) · Published by Druglandscape Ltd.