Permanent and Induced Magnets
Understand Permanent and Induced Magnets for GCSE Physics with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. Permanent magnets are always magnetic, while induced magnets become magnetic only in a magnetic field; like poles repel and unlike poles attract.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
The poles of a magnet are the places where the magnetic forces are strongest. Like poles repel and unlike poles attract, and this is a non-contact force.
A permanent magnet produces its own magnetic field all the time. An induced magnet is a material that becomes magnetic only when it is placed in a magnetic field, and it loses most or all of its magnetism quickly when removed from that field.
The crucial consequence is that the force between a permanent magnet and an induced magnet is always attraction. This is why a magnet attracts an unmagnetised iron nail regardless of which pole is presented — the nail becomes induced with the opposite pole facing the magnet.
Revision notes
Poles and forces
The poles of a magnet are where the magnetic forces are strongest.
Like poles repel; unlike poles attract. This is a non-contact force, acting without the magnets touching. Magnetically hard materials keep their magnetism; magnetically soft materials lose it easily.
Permanent and induced magnets
A permanent magnet produces its own magnetic field all the time.
An induced magnet becomes magnetic only when placed in a magnetic field, and it loses most or all of its magnetism quickly when removed.
Always attraction
The force between a permanent magnet and an induced magnet is always one of attraction.
The induced magnet develops the opposite pole facing the permanent magnet, whichever pole is presented. This is why a magnet picks up iron nails either way round.
Key points
- Poles are where magnetic forces are strongest.
- Like poles repel and unlike poles attract.
- Magnetic force is a non-contact force.
- A permanent magnet always has its own field.
- An induced magnet is magnetic only in a field.
- Induced magnetism always causes attraction.
Worked examples
Example 1
State the difference between a permanent magnet and an induced magnet. [2 marks]
Model answer
A permanent magnet produces its own magnetic field all the time (1 mark). An induced magnet only becomes magnetic when placed in a magnetic field, and loses most or all of its magnetism when removed (1 mark).
Example 2
Explain why a magnet attracts an unmagnetised iron nail whichever pole is presented. [3 marks]
Model answer
The nail becomes an induced magnet in the magnet's field (1 mark). The pole induced nearest the magnet is always the opposite pole (1 mark), so the force between them is always attraction (1 mark).
Example 3
State how you could tell whether a metal bar is a permanent magnet. [2 marks]
Model answer
Bring each pole of a known magnet near it in turn (1 mark). If it is repelled by one of them it must be a permanent magnet, because induced magnets are only ever attracted (1 mark).
Common mistakes
Saying induced magnets can repel.
Induced magnetism always produces attraction.
Saying attraction proves an object is a magnet.
Only repulsion proves it — attraction could be induced magnetism.
Confusing magnetically hard and soft.
Hard materials keep their magnetism; soft materials lose it quickly.
Saying magnetic force needs contact.
It is a non-contact force.
Exam tips
- Remember only repulsion proves permanent magnetism.
- Explain induced magnetism through the opposite pole forming.
- Say non-contact force when describing magnetic interaction.
- Distinguish permanent from induced clearly.
Key terms
- Pole
- Where the magnetic force is strongest.
- Permanent magnet
- A magnet producing its own field all the time.
- Induced magnet
- A material magnetic only while in a magnetic field.
- Non-contact force
- A force acting without objects touching.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.