# A student investigates how the resistance of a component changes as it heats up during use. At room temperature, the component allows a large current to pass through it. After several minutes of use, the student notices the current has decreased even though the voltage has not changed. Explain, in terms of particles, why the resistance of the component increases as its temperature rises.

> Eduqas A-Level Physics — 2.1 Conduction and resistance · Explain · 5 marks

> A component is connected to a fixed voltage supply. When first switched on, the current through the component is large. After several minutes, the current falls noticeably.

## Mark scheme (5 marks)

1. The metal component contains free (delocalised) electrons that carry charge through it
2. As temperature increases, the ions / atoms in the metal vibrate more / with greater amplitude
3. The more vigorously vibrating ions obstruct / collide with the free electrons more frequently
4. This makes it harder for the electrons to move through the material / the electrons are slowed down more, so resistance increases
5. Because voltage is unchanged and resistance has increased, the current decreases (linking back to the observation)

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Physics](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-investigates-how-the-resistance-229f1fa6) · Published by Druglandscape Ltd.