# An engineer is designing a solenoid for use in an electronic locking system. Explain how the engineer could increase the strength of the magnetic field produced by the solenoid.

> OCR A-Level Physics A (H556) — 4.4 Waves · Explain · 5 marks

> A solenoid is a coil of wire that produces a magnetic field when current flows through it. The engineer needs the strongest possible magnetic field to ensure the lock operates reliably.

## Mark scheme (5 marks)

1. Increase the number of turns (coils) of wire in the solenoid
2. Because more turns cause more magnetic field lines to align / overlap, producing a stronger combined field
3. Increase the current flowing through the solenoid
4. Insert an iron core inside the solenoid
5. Because it is easier for magnetic field lines to pass through iron than through air, so the field is concentrated and strengthened

## Key terms

- [solenoid](https://www.gradenine.co.uk/glossary/solenoid)
- [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-is-designing-a-solenoid-1a77918a) · Published by Druglandscape Ltd.