# A wind turbine converts kinetic energy from moving air into electrical energy. Some energy is dissipated as heat due to friction in the turbine's moving parts and resistance in its electrical components. Explain how the efficiency of the wind turbine could be improved, and explain what is meant by efficiency in this context.

> OCR GCSE Physics A: Gateway Science (J249) — P5.2 Power and efficiency · Explain · 4 marks

> A wind turbine is used to generate electricity for a remote farmhouse. Engineers are looking for ways to make the turbine operate more efficiently.

## Mark scheme (4 marks)

1. Efficiency is the ratio of useful output energy transfer to total energy input
2. Efficiency can never exceed 1 (or 100%) because energy cannot be created or destroyed (conservation of energy)
3. Lubrication of the moving parts reduces friction, which reduces heat energy dissipated as waste
4. Reducing current in the electrical components decreases power lost as heat in the wires (power loss = I²R), improving efficiency

## Key terms

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

## Related

- [Revision notes for OCR GCSE Physics A: Gateway Science (J249)](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-wind-turbine-converts-kinetic-energy-edfe88fb) · Published by Druglandscape Ltd.