# A student has two identical-looking steel rods. One rod is a permanent magnet and the other is unmagnetised. The student is only allowed to use the two rods themselves to find out which one is the permanent magnet. Explain how the student can identify the permanent magnet.

> WJEC GCSE Physics (Wales) — 2.5 Magnetism and electromagnetism · Explain · 4 marks

## Mark scheme (4 marks)

1. Hold one rod still and bring an end of the second rod close to each end of the first rod in turn (or a described systematic testing method)
2. If the rods attract at both ends (or repel at one end), at least one is a magnet; but to distinguish them, test the middle of one rod against the end of the other
3. The unmagnetised rod will always attract the permanent magnet (because it becomes induced/temporarily magnetised), so attraction alone does not identify the permanent magnet
4. The permanent magnet is the rod whose end repels the end of the other rod, OR the permanent magnet is the one that attracts the middle of the other rod (whereas a non-magnet's middle shows no attraction to either rod)

## Key terms

- [permanent magnet](https://www.gradenine.co.uk/glossary/permanent-magnet)
- [unmagnetised](https://www.gradenine.co.uk/glossary/unmagnetised)

## Related

- [Revision notes for WJEC GCSE Physics (Wales)](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-has-two-identical-looking-steel-4a9155a7) · Published by Druglandscape Ltd.