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This lesson covers how electromagnets are constructed, their advantages over permanent magnets and their applications, as required by the Edexcel GCSE Combined Science specification (1SC0). Electromagnets are used in a huge number of everyday devices because they can be switched on and off.
An electromagnet is a solenoid (coil of wire) with a soft iron core inside it. When current flows through the coil, the iron core becomes strongly magnetised. When the current is turned off, the iron core loses its magnetism almost immediately.
| Component | Role |
|---|---|
| Coil of insulated wire | Carries the current that generates the magnetic field |
| Soft iron core | Becomes a strong temporary magnet; concentrates the field |
| Power supply | Provides the current to switch the electromagnet on/off |
| Property | Soft Iron | Steel |
|---|---|---|
| Easily magnetised? | Yes | Yes |
| Easily demagnetised? | Yes — loses magnetism when current stops | No — retains magnetism (hard magnetic material) |
| Suitable for electromagnets? | Yes | No (would stay magnetised) |
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