# Explain what happens to a plotting compass when it is placed at different positions around a bar magnet, and describe how this can be used to draw the magnetic field pattern around the magnet.

> Eduqas A-Level Physics — 4.4 Magnetic fields · Explain · 5 marks

> A student places a plotting compass at several positions around a bar magnet on a piece of paper and marks the direction the needle points each time.

## Mark scheme (5 marks)

1. The compass needle points in the direction of the magnetic field at that position (the needle aligns with the field line).
2. The north pole of the compass needle points from the north pole of the bar magnet toward the south pole (field lines go from north to south outside the magnet).
3. A dot is marked at the tip of the compass needle (or the position is marked), then the compass is moved to that new position and the process is repeated.
4. Joining the sequence of dots produces a field line, and arrows must be added to show direction.
5. The field lines are closest together (most dense) near the poles, showing the field is strongest there.

## Key terms

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

## 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/explain-what-happens-to-a-plotting-3e55885f) · Published by Druglandscape Ltd.