# Explain how the magnetic effect of current in a wire can be increased, and describe how the shape of the magnetic field around a long straight current-carrying wire differs from that around a solenoid carrying the same current.

> AQA A-Level Physics (7408) — 3.7.5 Magnetic Fields · Explain · 5 marks

## Mark scheme (5 marks)

1. The magnetic field strength around a wire can be increased by increasing the current
2. The magnetic field strength can also be increased by winding the wire into a coil / solenoid (or adding more turns)
3. The field around a long straight wire consists of concentric circles centred on the wire
4. The field inside a solenoid is uniform (parallel and evenly spaced field lines along the axis)
5. The field outside a solenoid resembles that of a bar magnet (with a north and south pole at each end)

## Key terms

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

## Related

- [Revision notes for AQA A-Level Physics (7408)](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-magnetic-effect-of-a80dcbd9) · Published by Druglandscape Ltd.