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Electromagnets are incredibly versatile because they can be switched on and off. In this lesson you will explore key applications of electromagnets and understand why they are preferred over permanent magnets in many situations. This maps to AQA GCSE Combined Science Trilogy (8464) specification section 6.7.2.
The key advantage of an electromagnet over a permanent magnet is that an electromagnet can be switched on and off by controlling the current. Its strength can also be varied by changing the current or the number of turns.
| Feature | Permanent Magnet | Electromagnet |
|---|---|---|
| Switchable | No — always on | Yes — switch on/off with current |
| Adjustable strength | No — fixed strength | Yes — vary current or turns |
| Retains magnetism | Yes | Only while current flows |
| Power source needed | No | Yes — needs a current |
A large electromagnet is attached to a crane in a scrapyard.
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