# A student wraps a coil of wire around a soft iron core and connects it to a battery to make an electromagnet. Explain how the electromagnet is able to pick up iron nails and why the nails fall off when the battery is disconnected.

> Cambridge International IGCSE Physics (0625) — 4.5 Electromagnetic effects · Explain · 4 marks

## Mark scheme (4 marks)

1. The current through the coil creates a magnetic field (around the coil/core).
2. The magnetic field induces magnetism in the soft iron core / the soft iron core becomes a temporary (induced) magnet.
3. The induced magnetism attracts the iron nails / the iron nails are attracted to the magnetic field of the electromagnet.
4. When the battery is disconnected, the current stops, the magnetic field disappears, and the soft iron core loses its magnetism, so the nails fall off.

## Key terms

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

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](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-wraps-a-coil-of-f4304aa2) · Published by Druglandscape Ltd.