# An electric motor is used in a food blender to spin the blades. Explain how the motor produces continuous rotation, referring to the forces acting on the coil of wire inside the motor.

> OCR A-Level Physics A (H556) — 4.1 Charge and current · Explain · 5 marks

> A food blender uses an electric motor to spin its blades at high speed. Inside the motor, a coil of current-carrying wire sits between two permanent magnets.

## Mark scheme (5 marks)

1. The current-carrying coil experiences a force because it is placed in a magnetic field (motor effect / the two magnetic fields interact)
2. The two sides of the coil that are perpendicular to the magnetic field experience forces in opposite directions
3. These opposite forces cause the coil to rotate (rather than translate)
4. Fleming's Left-Hand Rule can be used to determine the direction of the force on each side of the coil
5. The motor continues to rotate because the current direction (or the connection via a split-ring commutator) ensures the forces always act in the same rotational sense / the coil keeps spinning as long as current flows

## 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)

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Source: [GradeNine](https://www.gradenine.co.uk/q/an-electric-motor-is-used-in-d84c0edb) · Published by Druglandscape Ltd.