# A kettle element is made from a long, thin wire. When the kettle is switched on, the current through the element causes it to heat up. Explain why the resistance of the kettle element increases as it heats up, and describe how this affects the current flowing through the element.

> OCR A-Level Physics B: Advancing Physics (H557) — 3.4 Materials · Explain · 5 marks

> A kettle element is a resistor made from a long, thin wire that heats water when a current passes through it. As the element warms up, its electrical properties change.

## Mark scheme (5 marks)

1. As current flows, electrons collide with atoms in the wire / resistor
2. Energy is transferred to the atoms, causing them to vibrate more
3. Increased vibration of atoms makes it more difficult for electrons to flow through the wire
4. This causes the resistance of the element to increase
5. As resistance increases, the current through the element decreases (for the same potential difference)

## Key terms

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

## Related

- [Revision notes for OCR A-Level Physics B: Advancing Physics (H557)](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-kettle-element-is-made-from-0d47d5b6) · Published by Druglandscape Ltd.