# Explain why electricity is transmitted across the National Grid at very high voltages rather than at low voltages.

> Eduqas GCSE Physics — 1.2 Generating electricity · Explain · 4 marks

## Mark scheme (4 marks)

1. High voltage reduces the current in the power cables
2. Lower current means less energy is lost/wasted (as heat) in the power cables
3. This makes the transmission more efficient
4. Power cables are metal wires, so some energy loss as heat is unavoidable / cannot be completely eliminated

## Key terms

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

## 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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-electricity-is-transmitted-across-6677cf7e) · Published by Druglandscape Ltd.