This key facts covers Electromagnets within Magnetic Fields for GCSE Physics. Revise Magnetic Fields in Magnetism for GCSE Physics with 14 exam-style questions and 12 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 5 of 13 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
⚡ Electromagnets
What they are: Magnets created by electric current flowing through a coil of wire.
Advantages over permanent magnets:
- Can be switched ON and OFF
- Strength can be controlled by varying current
- Polarity can be reversed by reversing current
How to make a stronger electromagnet:
- Increase the current
- Increase the number of turns/coils
- Add a soft iron core (not steel — it would stay magnetised!)
Uses: Scrapyard cranes, MRI machines, electric bells, loudspeakers, relays
Quick Check: Why is a soft iron core used in an electromagnet rather than a steel core?
Soft iron is used because it is an induced (temporary) magnet — it becomes magnetised when current flows but loses its magnetism immediately when the current is switched off. Steel would retain its magnetism after the current stops (it's a hard magnetic material), making the magnet impossible to switch off.
Practice questions for Magnetic Fields
What happens when two like magnetic poles (e.g. north and north) are brought close together?
State the rules for the attraction and repulsion of magnetic poles.