# Explain why electricity is transmitted across the National Grid at high voltage and low current.

> AQA GCSE Physics (8463) — 4.7.3 Induced potential, transformers and the National Grid (Phys only) · Explain · 4 marks

> The National Grid transmits electrical energy from power stations to homes and businesses across the country. Step-up transformers are used at power stations before the electricity enters the transmission cables.

## Mark scheme (4 marks)

1. High current causes greater energy loss (as heat) in the transmission cables
2. Transmitting at high voltage allows the current to be low (for the same power transferred)
3. Low current means less energy is wasted / lost as heat in the cables
4. This makes transmission more efficient (less energy wasted overall)

## Key terms

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

## 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-electricity-is-transmitted-across-ffc9e72f) · Published by Druglandscape Ltd.