IGCSE Physics Simple Phenomena of Magnetism Questions and Worked Solutions (4.1) | 0625

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IGCSE Physics 0625 · Topic 4.1

IGCSE Physics Simple Phenomena of Magnetism Questions and Worked Solutions

50 topic-wise practice questions on Simple Phenomena of Magnetism (Unit 4: Electricity and Magnetism), written to the Cambridge IGCSE Physics 0625 syllabus for 2026–2028, each with a step-by-step worked solution.

50 questions31 Core9 Extended10 Challenge112 marksTextbook §4.1 · pp. 176–183
Questions tagged Core are for all candidates (Papers 1 & 3). Questions tagged Extended are Supplement content (Papers 2 & 4). Questions 41–50 are harder Challenge questions. Try each question first, then tap Show solution to check your working.

Topic guide: Simple Phenomena of Magnetism

Magnets have north and south poles. Like poles repel and unlike poles attract. Magnetic materials can be magnetised by induction. A magnetic field is the region around a magnet where a magnetic pole feels a force.

Key formulas

No equations to learn in this subtopic — learn field patterns and properties.

Prerequisite knowledge

  • Idea of a force (1.5.1)

Exam tips & common mistakes

  • Only repulsion proves an object is a magnet
  • Arrows on field lines go from N to S outside the magnet
  • Field lines never cross

Key facts from the syllabus (4.1)

  • Like poles repel; unlike poles attract; magnets attract magnetic materials
  • Induced magnetism: a magnetic material near a magnet becomes a magnet
  • Soft iron: easily magnetised, easily loses magnetism (temporary, electromagnets). Steel: harder to magnetise, keeps magnetism (permanent)
  • Magnetic materials: iron, steel, nickel, cobalt; non-magnetic: copper, aluminium, wood, plastic
  • Field lines go from N to S; the direction of the field is the direction of the force on a N pole
  • Plot fields with a plotting compass or iron filings
  • Uses: permanent magnets (fridge seals, loudspeakers); electromagnets (cranes, relays, MRI)
  • Extended forces are due to interacting fields; closer field lines mean a stronger field

Textbook: §4.1 Simple phenomena of magnetism, pp. 176–183

1
Core[1 mark]

State what happens when two north poles are brought close together.

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Method: Like poles repel.

They repel
2
Core[1 mark]

State what happens when a north pole and a south pole are brought close together.

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Method: Unlike poles attract.

They attract
3
Core[2 marks]

Explain why repulsion, not attraction, is the only reliable test that an object is a magnet.

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Method: Magnets attract unmagnetised magnetic materials too.

A magnet attracts unmagnetised magnetic materials as well as opposite poles, but only another magnet can repel it
4
Core[2 marks]

Describe induced magnetism.

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Method: Material becomes magnetised near a magnet.

A magnetic material placed near a magnet becomes a magnet itself (with the opposite pole nearest the magnet)
5
Core[3 marks]

State the differences between temporary magnets (soft iron) and permanent magnets (steel).

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Method: Soft iron easily magnetised and loses it; steel keeps it.

Soft iron is easily magnetised and easily loses its magnetism (temporary); steel is harder to magnetise but keeps its magnetism (permanent)
6
Core[2 marks]

State the difference between magnetic and non-magnetic materials and give an example of each.

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Method: Attracted or not.

Magnetic materials are attracted by a magnet (e.g. iron, steel, nickel, cobalt); non-magnetic are not (e.g. copper, aluminium, wood)
7
Core[1 mark]

Define a magnetic field.

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Method: Region of force on a pole.

A region in which a magnetic pole experiences a force
8
Core[2 marks]

Describe the magnetic field pattern around a bar magnet.

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Method: Lines from N to S.

Field lines leave the N pole and curve round to enter the S pole; they are closest together at the poles
9
Core[1 mark]

State the direction of a magnetic field at a point.

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Method: Force on N pole.

The direction of the force on the N pole of a magnet at that point
10
Core[3 marks]

Describe how to plot the magnetic field lines around a bar magnet using a plotting compass.

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Method: Dot-to-dot method.

Place the magnet on paper; put a compass near one pole and mark where the needle points; move the compass to that dot and repeat; join the dots and add arrows from N to S
11
Core[2 marks]

Describe how iron filings can show the pattern of a magnetic field.

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Method: Sprinkle and tap.

Place paper over the magnet, sprinkle iron filings and tap gently; the filings line up along the field lines
12
Core[2 marks]

State two uses of permanent magnets.

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Method: e.g. fridge doors, loudspeakers.

e.g. fridge door seals, loudspeakers, compasses, motors
13
Core[2 marks]

State two uses of electromagnets.

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Method: Can be switched off.

e.g. scrapyard cranes, relays, electric bells, MRI scanners
14
Core[2 marks]

Explain why the core of an electromagnet is made of soft iron, not steel.

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Method: Soft iron loses magnetism.

Soft iron becomes strongly magnetised but loses its magnetism when the current is switched off
15
Core[2 marks]

A steel paper clip hangs from a magnet and a second clip hangs from the first. Explain why.

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Method: Induced magnetism.

The first clip has magnetism induced in it, so it attracts the second clip
16
Core[2 marks]

State which of copper, iron, aluminium and nickel are attracted by a magnet.

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Method: Magnetic materials.

Iron and nickel
17
Core[2 marks]

Name three magnetic elements.

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Method: Fe, Ni, Co.

Iron, nickel and cobalt
18
Core[2 marks]

A bar magnet is suspended freely. State which direction it points and why.

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Method: Earth's field.

North–south, because it aligns with the Earth's magnetic field
19
Core[2 marks]

An iron nail is stroked with a magnet. Describe what happens to the nail.

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Method: Magnetised.

It becomes magnetised (a permanent or semi-permanent magnet)
20
Core[2 marks]

Describe one way to demagnetise a magnet.

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Method: Heat/hammer/a.c.

Heat it strongly, hammer it, or place it in a coil carrying a.c. and slowly withdraw it
21
Core[2 marks]

An unmagnetised iron bar is placed near the N pole of a magnet. State the pole induced at the near end of the bar.

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Method: Opposite pole.

A S pole
22
Core[2 marks]

Explain why a steel bar is used for a permanent magnet.

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Method: Retains magnetism.

Steel keeps its magnetism once magnetised
23
Core[2 marks]

Describe how you would test whether a metal rod is a magnet, a magnetic material or non-magnetic.

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Method: Repulsion test.

Bring each end near a magnet's pole: repulsion at one end means a magnet; attraction at both ends means magnetic material; no effect means non-magnetic
24
Core[2 marks]

State the direction a compass needle points when placed near the N pole of a bar magnet.

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Method: Away from N.

Its N end points away from the N pole of the magnet
25
Core[2 marks]

State where the magnetic field around a bar magnet is strongest.

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Method: Poles.

At the poles
26
Core[2 marks]

Explain why aluminium cans can be separated from steel cans using a magnet.

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Method: Magnetic vs non-magnetic.

Steel is magnetic and is attracted; aluminium is not
27
Core[2 marks]

State one use of an electromagnet in a hospital.

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Method: MRI.

MRI scanner (or removing metal splinters from eyes)
28
Core[2 marks]

State one use of a permanent magnet in a home.

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Method: Fridge seal, speakers.

Fridge door seal (or loudspeaker, cupboard catches)
29
Core[2 marks]

Describe the pattern of iron filings between two unlike poles placed close together.

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Method: Straight lines across.

Lines run straight across from one pole to the other
30
Core[2 marks]

A paper clip is attracted to a magnet through a sheet of paper. State what this tells you about the magnetic field.

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Method: Passes through.

The magnetic field passes through non-magnetic materials such as paper
31
Core[2 marks]

Explain why a magnetic field is drawn with arrows.

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Method: Direction.

To show the direction of the field (the direction of force on a N pole)
32
Extended[1 mark]

Explain what causes the forces between magnets.

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Method: Field interaction.

Magnetic forces are due to interactions between magnetic fields
33
Extended[1 mark]

State how the relative strength of a magnetic field is shown by field lines.

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Method: Spacing.

The closer the field lines, the stronger the field
34
Extended[2 marks]

Describe the magnetic field between a N pole and a S pole facing each other.

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Method: Uniform field.

The lines go straight across from N to S, evenly spaced (a uniform field)
35
Extended[2 marks]

Describe the field between two N poles facing each other.

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Method: Neutral point.

The lines from each pole push apart and bend away; there is a neutral point midway where the field is zero
36
Extended[2 marks]

Field lines are close together near the poles of a magnet. State what this shows.

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Method: Strength.

The field is strongest there
37
Extended[2 marks]

Explain why two N poles repel in terms of fields.

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Method: Field interaction.

Their fields interact and push against each other, producing a force of repulsion
38
Extended[2 marks]

Describe what happens to the field line spacing as you move away from a bar magnet.

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Method: Spread out.

The lines spread further apart, showing a weaker field
39
Extended[2 marks]

Sketch and describe the field between two N poles facing each other.

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Method: Lines turn away.

Lines from each N pole curve away from each other; there is a neutral point between them with no field
40
Extended[2 marks]

Explain why iron filings line up along field lines.

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Method: Induced magnetism.

Each filing becomes a tiny induced magnet and turns to line up with the field

Challenge questions

Harder, multi-step questions at the top end of the exam. Attempt these once you are confident with the questions above.

41
ChallengeCore[4 marks]

You are given three identical-looking bars: a magnet, an iron bar and an aluminium bar. Describe how to identify each using only one of the bars and a compass.

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Method: Repulsion test and attraction.

Bring each end of each bar to the compass: the magnet repels one end of the needle; the iron bar attracts both ends but never repels; the aluminium has no effect
42
ChallengeCore[4 marks]

Explain why an iron nail hanging from a magnet can hold a second nail, and what happens when the magnet is removed if the nails are soft iron and if they are steel.

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Method: Induced magnetism.

The first nail is magnetised by induction and attracts the second; soft iron loses its magnetism so the nails fall; steel keeps some magnetism so they may stay together
43
ChallengeCore[4 marks]

Describe how to plot the field around a bar magnet using a compass, and explain how the pattern shows where the field is strongest.

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Method: Dot method.

Mark the needle direction, move the compass along, join dots and add arrows N to S; lines are closest near the poles where the field is strongest
44
ChallengeCore[3 marks]

Explain why the core of an electromagnet in a scrapyard crane is soft iron, whereas a compass needle is steel.

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Method: Temporary vs permanent.

Soft iron magnetises strongly and loses magnetism when the current is off so the scrap can be dropped; a compass needle must stay magnetised
45
ChallengeCore[4 marks]

Explain why a magnet attracts an unmagnetised iron bar regardless of which end is brought near it, but a second magnet may be attracted or repelled.

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Method: Induced opposite pole.

The magnet induces an opposite pole in the near end of the iron, so it always attracts; a magnet's pole is fixed, so like poles repel
46
ChallengeCore[3 marks]

Explain why a steel paper clip near a strong magnet remains slightly magnetised after the magnet is removed.

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Method: Steel retains.

Steel is a permanent magnetic material, so induced magnetism is partly retained
47
ChallengeExtended[4 marks]

Two bar magnets are placed in line with N poles facing, 10 cm apart. Sketch and describe the field and state where a compass would show no preferred direction.

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Method: Neutral point.

Field lines from each N pole curve away from each other; at the midpoint the fields cancel (neutral point) so the compass shows no preferred direction (only Earth's field)
48
ChallengeExtended[3 marks]

Explain, in terms of field lines, why the force between two magnets weakens as they are moved apart.

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Method: Field spreads.

Field lines spread out further from a magnet, so the field (and interaction) is weaker
49
ChallengeExtended[4 marks]

Explain why the force between two magnets is said to be due to interacting fields, using the example of two S poles repelling.

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Method: Fields push.

Each magnet produces a field; where the fields from two S poles meet they oppose, producing a force pushing the magnets apart
50
ChallengeExtended[3 marks]

Describe a uniform magnetic field and explain how one can be produced between two magnets.

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Method: Parallel equally spaced.

Parallel, equally spaced lines; produced between opposite poles (N facing S) close together
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