# A student connects a battery, a lamp, and a switch in a series circuit. The student then adds a second identical lamp in series with the first lamp. Explain what happens to the brightness of the original lamp when the second lamp is added, and why.

> OCR GCSE Physics A: Gateway Science (J249) — P3.2 Simple circuits · Explain · 4 marks

> A student is investigating how adding components to a series circuit affects the behaviour of the circuit. The battery used has a fixed voltage.

## Mark scheme (4 marks)

1. The original lamp becomes dimmer (after the second lamp is added)
2. Adding a second lamp in series increases the total resistance of the circuit
3. Because the voltage of the battery is fixed, the increased resistance causes the current in the circuit to decrease
4. A smaller current through the lamp means less power is transferred, so the lamp is dimmer

## Key terms

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

## Related

- [Revision notes for OCR GCSE Physics A: Gateway Science (J249)](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-a-battery-a-05292994) · Published by Druglandscape Ltd.