# A student uses an electric fan heater to warm a room. Explain why the efficiency of the fan heater can never reach 100%, and describe TWO ways in which the efficiency of a different appliance, such as a motor, could be improved.

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

> A fan heater is designed to transfer electrical energy into useful thermal energy and kinetic energy of the air. In practice, some energy is always transferred in ways that do not directly serve this purpose.

## Mark scheme (4 marks)

1. Energy cannot be created or destroyed (conservation of energy), so some energy will always be transferred as waste energy transfer rather than useful energy transfer.
2. Efficiency can never exceed 1 (or 100%) because the useful output energy transfer can never be greater than the total energy input.
3. Lubrication — applying a lubricant such as oil to reduce friction between moving surfaces, which reduces waste energy transfer.
4. Thermal insulation — adding an insulating material to reduce the transfer of heat from the appliance to its surroundings, so more energy goes to the useful output.

## Key terms

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

## Related

- [Revision notes for Eduqas GCSE Physics](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-student-uses-an-electric-fan-8f23f170) · Published by Druglandscape Ltd.