# An engineer designs a solenoid to be used as an electromagnet in a factory to lift steel objects. Explain how the engineer could increase the strength of the magnetic field produced by the solenoid.

> OCR A-Level Physics A (H556) — 4.5 Quantum physics · Explain · 5 marks

> A solenoid is a wire wrapped into the shape of a coil. When current flows through the solenoid, a magnetic field is produced. The engineer wants to make the electromagnet as powerful as possible.

## Mark scheme (5 marks)

1. Increase the number of turns (coils) of wire in the solenoid
2. Increase the size of the current flowing through the solenoid
3. Insert an iron core inside the solenoid
4. The iron core increases field strength because it is easier for magnetic field lines to pass through iron than through air
5. Increasing the number of turns causes the individual magnetic fields around each coil to align and combine to form a stronger overall field

## Key terms

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

## Related

- [Revision notes for OCR A-Level Physics A (H556)](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/an-engineer-designs-a-solenoid-to-a5867431) · Published by Druglandscape Ltd.