# A hospital uses a large electric motor to drive a ventilation fan. The motor contains a coil of wire that rotates between two permanent magnets. Explain how the electric motor produces rotation.

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

> Electric motors are used in many devices in hospitals, from ventilation fans to pumps. Inside each motor, a coil of current-carrying wire is placed between the poles of permanent magnets.

## Mark scheme (5 marks)

1. Current flows through the coil of wire, producing a magnetic field around it
2. The magnetic field of the coil interacts with the magnetic field of the permanent magnets
3. A force is exerted on each side of the coil (motor effect / force on a current-carrying wire in a magnetic field)
4. The forces on opposite sides of the coil act in opposite directions
5. These opposing forces cause the coil to rotate

## Key terms

- [electric motor](https://www.gradenine.co.uk/glossary/electric-motor)
- [permanent magnet](https://www.gradenine.co.uk/glossary/permanent-magnet)

## 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/a-hospital-uses-a-large-electric-7cf7cb5e) · Published by Druglandscape Ltd.