# Explain why the National Grid transmits electrical power at a high potential difference rather than a high current, and describe how this is made possible when electrical power leaves a power station.

> AQA GCSE Physics (8463) — 4.2.5 The National Grid · Explain · 4 marks

## Mark scheme (4 marks)

1. Transmitting at high potential difference means the current is low (for the same power)
2. A lower current means less energy is lost (as heat) in the transmission cables
3. A step-up transformer increases the potential difference from the power station before the power enters the transmission cables
4. Step-down transformers then reduce the potential difference to a safe, usable level for consumers

## Key terms

- [potential difference](https://www.gradenine.co.uk/glossary/potential-difference)
- [National Grid](https://www.gradenine.co.uk/glossary/national-grid)

## Related

- [Revision notes for AQA GCSE Physics (8463)](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/explain-why-the-national-grid-transmits-f1447b6a) · Published by Druglandscape Ltd.