# Explain how a plotting compass can be used to map the magnetic field around a bar magnet, and describe the pattern of field lines that would be produced.

> WJEC A-Level Physics (Wales) — 4.4 Magnetic fields · Explain · 5 marks

> A student places a bar magnet flat on a piece of paper and uses a plotting compass to investigate the magnetic field around it.

## Mark scheme (5 marks)

1. Place the plotting compass near one pole of the bar magnet and mark the direction the needle points
2. Move the compass to the new marked position and repeat, joining the dots to form a field line
3. The field lines go from the north pole to the south pole of the bar magnet
4. Field lines are closest together (most dense) near the poles, showing the field is strongest there
5. Field lines never cross each other

## Key terms

- [plotting compass](https://www.gradenine.co.uk/glossary/plotting-compass)
- [magnetic field](https://www.gradenine.co.uk/glossary/magnetic-field)
- [field lines](https://www.gradenine.co.uk/glossary/field-lines)

## Related

- [Revision notes for WJEC A-Level 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/explain-how-a-plotting-compass-can-367f118e) · Published by Druglandscape Ltd.