# A recycling plant uses an electric motor to drive a conveyor belt that separates magnetic materials from non-magnetic waste. Explain how the electric motor produces rotation.

> OCR A-Level Physics A (H556) — 4.2 Energy, power and resistance · Explain · 5 marks

> An electric motor contains a coil of wire placed between two permanent magnets. When a direct current is passed through the coil, the motor begins to rotate, driving the conveyor belt.

## Mark scheme (5 marks)

1. A current-carrying wire in a magnetic field experiences a force (motor effect / force on a wire)
2. The two sides of the coil that are perpendicular to the magnetic field experience forces in opposite directions
3. These opposing forces cause the coil to rotate
4. Fleming's left-hand rule can be used to determine the direction of the force on each side of the coil
5. The magnitude of the force (and therefore the speed of rotation) depends on the magnetic flux density of the field and/or the size of the current

## Key terms

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

## 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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-recycling-plant-uses-an-electric-c1d23d4b) · Published by Druglandscape Ltd.