# A washing machine transfers electrical energy to wash clothes. Describe the useful energy transfer and the waste energy transfer that occur when the washing machine is in use, and explain one way in which the efficiency of the washing machine could be improved.

> Eduqas GCSE Physics — 1.3 Making use of energy · Describe · 4 marks

> A washing machine uses an electric motor to spin a drum. As the drum spins, it gets warm and produces a humming sound.

## Mark scheme (4 marks)

1. The useful energy transfer is electrical energy transferred to kinetic energy (of the spinning drum / motor).
2. Waste energy transfers include thermal (heat) energy and/or sound energy, which do not directly serve the purpose of the machine.
3. Lubrication of the moving parts (motor/drum bearings) reduces friction between surfaces.
4. Reducing friction means less waste energy transfer (as heat/sound), so a greater proportion of the input energy is usefully transferred, increasing efficiency.

## Key terms

- [useful energy transfer](https://www.gradenine.co.uk/glossary/useful-energy-transfer)
- [waste energy transfer](https://www.gradenine.co.uk/glossary/waste-energy-transfer)
- [efficiency](https://www.gradenine.co.uk/glossary/efficiency)

## Related

- [Revision notes for Eduqas GCSE Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-washing-machine-transfers-electrical-energy-eb566011) · Published by Druglandscape Ltd.