AQA GCSE Combined Science Foundation (8464), Foundation tier · Physics › Magnetism and electromagnetism › Permanent and induced magnetism, magnetic forces and fields
Practise Poles of a magnet. 6 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
The poles of a magnet are the places where its magnetic forces are strongest. You need to describe how like and unlike poles affect each other, and the difference between a permanent magnet and an induced magnet. Expect 1 to 3 mark recall, 'describe' and 'explain' questions, often about magnets, nails or paper clips.
Key facts
Poles: north (seeking) and south (seeking); forces are strongest at the poles
Like poles repel; unlike poles attract
Magnetic attraction and repulsion are non-contact forces
Permanent magnet: produces its own magnetic field
Induced magnet: becomes a magnet only when placed in a magnetic field
Induced magnetism always causes attraction
An induced magnet loses most or all of its magnetism quickly when removed from the field
Magnetic materials: iron, steel, cobalt and nickel
Notes
Poles and forces
diagram
Every magnet has two poles: a north (seeking) pole and a south (seeking) pole.
The magnetic forces are strongest at the poles.
When two magnets are brought close together, they exert a force on each other.
Like poles repel (N and N, or S and S). Unlike poles attract (N and S).
The red arrows show the forces on each magnet.
The magnets do not have to touch, so magnetic attraction and repulsion are non-contact forces.
The forces get weaker as the magnets are moved further apart.
Permanent and induced magnets
A permanent magnet produces its own magnetic field all the time, e.g. a steel bar magnet.
An induced magnet is a material that becomes a magnet when it is placed in a magnetic field, e.g. an iron nail held near a bar magnet.
Induced magnetism always causes a force of attraction.
When it is taken out of the magnetic field, an induced magnet loses most or all of its magnetism quickly.
Iron loses its induced magnetism quickly, which is why it is used for the core of an electromagnet that must switch off. Steel keeps its magnetism, so it is used for permanent magnets.
How to answer each type of question
State whether two magnets attract or repel
1 to 2 marksGrade 3
Find which two poles are facing each other.
Like poles repel; unlike poles attract.
If one object is only a magnetic material (not a magnet), the answer is always attract.
Example. Two bar magnets, A and B, lie end to end on a table. The north pole of magnet A faces the south pole of magnet B. (a) State whether the magnets attract or repel each other. (b) Magnet B is turned round, so that its north pole faces magnet A. State whether the magnets now attract or repel.
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(a) Attract (1) (b) Repel (1)
Describe the difference between a permanent and an induced magnet
2 to 4 marksGrade 5
Say what a permanent magnet does: it produces its own magnetic field.
Say what an induced magnet is: a material that only becomes a magnet when it is in a magnetic field.
If asked what happens when the magnet is taken away, say the induced magnet loses (most of) its magnetism quickly.
Example. A bar magnet picks up an iron nail. A second iron nail hangs from the bottom of the first nail. (a) The first nail is an induced magnet. Describe the difference between a permanent magnet and an induced magnet. [2 marks] (b) The bar magnet is carefully pulled away from the top of the first nail. Suggest what happens to the second nail. Give a reason for your answer. [2 marks]
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(a) A permanent magnet produces its own magnetic field (1). An induced magnet only becomes a magnet when it is placed in a magnetic field (1). (b) The second nail falls off (1) because the first nail loses (most of) its magnetism quickly when it is no longer in the magnetic field (1).
Don’t lose marks
Saying an induced magnet can repel a magnet: induced magnetism always causes attraction.
Saying all metals are magnetic: copper, aluminium, gold and silver are not. Only iron, steel, cobalt and nickel are.
Saying the forces are strongest in the middle of a magnet: they are strongest at the poles.
Using attraction as proof that an object is a magnet.
Calling the poles 'positive' and 'negative': magnetic poles are north and south.
More tips
Memory tricks
Unlike poles attract, like poles repel: the same rule as for positive and negative electric charges.
'Attraction can fool you, repulsion proves it': only repulsion shows an object is a magnet.
ICoNS: Iron, Cobalt, Nickel, Steel are the magnetic materials.
'Induced' means 'in a field': an induced magnet is only a magnet while it is in a magnetic field.
Exam technique
Use the words 'attract' and 'repel'. Vague words such as 'react' or 'affect each other' do not get the mark.
In 'describe the difference' questions, write about both types of magnet, not just one.
If a question says an object becomes magnetised only while it is near a magnet, it is describing an induced magnet.
What each grade needs
What you need to be able to do, from the first marks up to the top grade.
Grade 3
State where a magnet's forces are strongestThe magnetic forces are strongest at the poles: the north (seeking) pole and the south (seeking) pole.
Grade 3
Predict attraction or repulsion between two polesLike poles (N and N, or S and S) repel; unlike poles (N and S) attract.
Grade 4
Identify magnetic forces as non-contact forcesMagnets attract or repel each other without touching, so these are non-contact forces.
Grade 5
Describe the difference between permanent and induced magnetsA permanent magnet produces its own magnetic field; an induced magnet only becomes a magnet when it is placed in a magnetic field.
Quick recall
Cover the answers and test yourself. The app has these as flashcards that come back just before you'd forget them.
A student holds two bar magnets close to each other. Where are the magnetic forces of a bar magnet strongest?
At the poles
Two magnets exert forces on each other without touching. What type of force is this?
A non-contact force
Give one everyday object that uses a permanent magnet.
A fridge magnet (or any similar example).
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
A student holds two bar magnets close to each other.
(a) The north pole of one magnet is brought close to the north pole of the other magnet. What happens? Tick (✓) one box.[1]
The magnets attract each other.
The magnets repel each other.
There is no force between the magnets.
(b) The force between the two magnets is an example of which type of force? Tick (✓) one box.[1]
Contact force
Friction
Non-contact force
Tension
(c) Where are the magnetic forces of a bar magnet strongest?[1]
(d) Name one magnetic material.[1]
Show the answer and mark scheme
(a)Answer: The magnets repel each other.
(b)Answer: Non-contact force
(c)Answer: At the poles
at the poles / at the ends
(d)Answer: Iron (or steel, cobalt or nickel)
iron / steel / cobalt / nickel
Question 2Medium7 marks
A student hangs a small iron nail from the north pole of a bar magnet. A second nail is then hung from the bottom of the first nail, and a third nail from the bottom of the second, forming a chain.
(a) Explain why the first nail is attracted to the magnet.[2]
(b) Explain why the second nail is attracted to the first nail.[1]
(c) The student carefully pulls the magnet away from the top nail. Describe and explain what happens to the chain of nails.[2]
(d) Describe the difference between a permanent magnet and an induced magnet.[2]
Show the answer and mark scheme
(a)Answer: The nail becomes an induced magnet, and induced magnetism always causes attraction.
the nail becomes an induced magnet (when it is in the magnetic field)
induced magnetism always causes a force of attraction
(b)Answer: The first nail has become a magnet and induces magnetism in the second nail.
the first nail is magnetised / is an induced magnet, so it induces magnetism in the second nail (which is attracted)
(c)Answer: The chain falls apart because the nails lose their induced magnetism quickly.
the nails fall apart / drop off
an induced magnet loses most or all of its magnetism quickly when it is removed from the magnetic field
(d)Answer: A permanent magnet has its own magnetic field; an induced magnet is only a magnet while it is in a magnetic field.
a permanent magnet produces its own magnetic field (all the time)
an induced magnet only becomes a magnet when it is placed in a magnetic field