# A maglev train uses electromagnets to levitate above a track. Explain how increasing the current through the electromagnets affects the force on the train, and describe one way a maglev train differs from a conventional train that uses permanent magnets attached to the track.

> OCR GCSE Physics A: Gateway Science (J249) — P3.3 Magnetism and the motor effect · Explain · 4 marks

> Maglev trains use the motor effect and electromagnetic principles to float above the track without wheels. Engineers can adjust the current supplied to the electromagnets to control the levitation force.

## Mark scheme (4 marks)

1. Increasing the current increases the strength of the magnetic field produced by the electromagnet
2. A stronger magnetic field results in a greater force on the train (greater levitation/upward force)
3. A maglev train's electromagnets can be switched off (or reversed), unlike a permanent magnet which cannot be turned off
4. A maglev train has no physical contact with the track (no friction between train and track) whereas a conventional wheeled train does

## Key terms

- [electromagnet](https://www.gradenine.co.uk/glossary/electromagnet)
- [permanent magnet](https://www.gradenine.co.uk/glossary/permanent-magnet)
- [current](https://www.gradenine.co.uk/glossary/current)

## 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)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-maglev-train-uses-electromagnets-to-172142a3) · Published by Druglandscape Ltd.