State two differences between a permanent magnet and a temporary (induced) magnet, and for each difference give one application that makes use of that property.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
1. A permanent magnet retains its magnetism when removed from a magnetic field; it produces its own magnetic field.
Application: a compass – the needle remains magnetised and points north.
2. A temporary (induced) magnet loses its magnetism when the external field is removed; its magnetism can be switched on and off.
Application: an electric motor – the coil becomes a temporary magnet only when current flows.
Application: a compass – the needle remains magnetised and points north.
2. A temporary (induced) magnet loses its magnetism when the external field is removed; its magnetism can be switched on and off.
Application: an electric motor – the coil becomes a temporary magnet only when current flows.
Examiner tips
- Use the word ‘retains’ for permanent and ‘loses’ for temporary to show clear contrast. Mention the ability to switch on/off for the temporary magnet. Give a specific example that relies on that property (e.g. motor for temporary).
Common mistakes
- Confusing the terms ‘permanent’ and ‘temporary’. Failing to state the property before giving the application. Using vague examples that do not clearly depend on the stated property.
Mark scheme (4 marks)
- A permanent magnet retains its magnetism when removed from a magnetic field / produces its own magnetic field, whereas a temporary magnet loses its magnetism when the magnetic field is removed.
- Application for permanent magnet that requires the property stated — e.g. compass or fridge magnet (always needs to be on / always producing a field).
- A temporary magnet can be switched on and off (its magnetism can be turned on and off by varying the current), whereas a permanent magnet cannot.
- Application for temporary magnet that requires the property stated — e.g. scrap metal crane / electric motor (needs to be switched on and off).
Key terms in this question
permanent magnet · temporary (induced) magnet
Related
- All Cambridge International IGCSE Physics (0625) revision notes →
- How to answer a "State" question →
- Decode the mark scheme abbreviations →
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