Simple Phenomena of Magnetism
PhysicsΒ· 4.1 (2026-2028 Syllabus)Β· 12 min read
1. Core: Properties of Magnets & Magnetic Materialsβ β ββββ± 3 min
Magnetic Material
A material that is attracted to a magnet, and can be made into a magnet. Only iron, cobalt, nickel and their alloys (e.g. steel) are magnetic at IGCSE level.
Example:
Steel is a magnetic alloy of iron and carbon; copper is non-magnetic.
Permanent magnets have two poles: north (N) and south (S). Like poles repel, unlike poles attract. The magnetic force is strongest at the poles, and weakest at the midpoint of a bar magnet.
A student has two identical steel bars: one is a permanent magnet, the other is unmagnetised. Describe a test to identify which is the magnet, without using any other equipment.
- 1
Hold one bar stationary, bring one end of the second bar to the middle of the stationary bar.
- 2
If there is strong attraction, the moving bar is the permanent magnet: the middle of a permanent magnet has no magnetic field, so only the moving magnet will attract the unmagnetised bar.
- 3
If there is no attraction, the stationary bar is the permanent magnet, as you are holding the unmagnetised bar to the neutral midpoint of the magnet.
Exam tip:
Always explicitly state repulsion is the only definitive test for a permanent magnet in written answers, not attraction.
2. Core: Magnetic Fields & Field Linesβ β ββββ± 4 min
Magnetic Field
The region around a magnet where a magnetic force acts on a magnetic material or another magnet.
Field lines never cross each other
Closer field lines = stronger magnetic field
Arrows on field lines point in the direction a free north pole would move
Draw and describe the magnetic field pattern around a bar magnet, marking the strongest field regions.
- 1
Draw a bar magnet, label N and S poles on opposite ends.
- 2
Draw curved lines from the N pole to S pole outside the magnet, getting further apart as you move away from the poles.
- 3
Mark the regions closest to the N and S poles as the strongest field areas, where field lines are closest together.
- 4
Add arrows to all lines pointing from N to S outside the magnet.
What direction do magnetic field lines point outside a bar magnet?
Reveal answer
From the north pole to the south pole βThis matches the direction a free north pole would move if placed in the field.
3. Core: Induced Magnetismβ β β βββ± 3 min
Induced Magnetism
Temporary magnetism created in a magnetic material when it is placed in a magnetic field. The induced pole closest to the permanent magnet is always the opposite pole, leading to attraction.
Example:
When an iron nail is held near a permanent magnet, the end of the nail closest to the magnet's N pole becomes an induced S pole, so the nail is attracted to the magnet.
Induced magnetism disappears as soon as the magnetic field is removed for soft magnetic materials (e.g. pure iron). Hard magnetic materials (like steel) retain some magnetism after the field is removed, so can be made into permanent magnets.
A permanent bar magnet is held touching one end of an unmagnetised steel paper clip. The other end of the paper clip now picks up a second unmagnetised paper clip. Explain why this happens.
- 1
The permanent magnet induces magnetism in the first paper clip: the end touching the permanent magnet becomes an opposite pole, the far end becomes the same pole as the end of the permanent magnet it is touching.
- 2
The first paper clip then induces magnetism in the second paper clip, with opposite poles on adjacent ends, leading to attraction between the two paper clips.
4. Extended Only: Magnetisation, Demagnetisation & Solenoid Fieldsβ β β β βExtended onlyβ± 5 min
Magnetisation methods: 1. Stroking a magnetic material with one pole of a permanent magnet in a single direction repeatedly; 2. Placing the material inside a solenoid with a large direct current (DC) flowing through it.
Demagnetisation methods: 1. Hammering the magnet repeatedly while facing east-west (away from Earth's magnetic field); 2. Heating the magnet to red hot and cooling while facing east-west; 3. Placing the magnet inside a solenoid carrying alternating current (AC) and slowly pulling it away from the coil.
Right-Hand Grip Rule for Solenoids
Used to find the polarity of a solenoid carrying DC current: grip the solenoid with your right hand, so your fingers point in the direction of current flow around the coil. Your outstretched thumb points to the north pole of the solenoid.
A solenoid has current flowing into the left end of the coil from the top of the windings, and out of the right end of the coil from the bottom. Use the right-hand grip rule to find which end of the solenoid is the north pole.
- 1
Visualise the current flow: at the left end of the solenoid, current travels clockwise around the coil; at the right end, current travels anticlockwise.
- 2
Grip the solenoid with your right hand, fingers curling in the direction of current flow (anticlockwise when looking at the right end, clockwise at the left end).
- 3
Your thumb points to the right, so the right end of the solenoid is the north pole.
Exam tip:
The magnetic field inside a solenoid is uniform: draw straight, parallel, evenly spaced field lines along the axis of the coil for exam answers.
5. Common Pitfalls
Wrong move:
Claiming attraction is a sure test for a permanent magnet
Why:
Magnetic materials are attracted to both poles of a magnet, so attraction cannot distinguish between a magnet and an unmagnetised magnetic material.
Correct move:
Only repulsion between two like poles confirms an object is a permanent magnet.
Wrong move:
Drawing magnetic field lines pointing from south to north outside a magnet
Why:
Field lines represent the direction a free north pole would move, so they always point away from north poles and towards south poles outside the magnet.
Correct move:
Draw field lines with arrows pointing NβS outside the magnet, and SβN inside the magnet.
Wrong move:
Classifying aluminium or copper as magnetic materials
Why:
Only iron, cobalt, nickel and their alloys are magnetic at IGCSE 0625 level; all other metals are non-magnetic.
Correct move:
Memorise the four magnetic materials: iron, cobalt, nickel, steel (alloy of iron).
Wrong move:
Using the left hand for the solenoid right-hand grip rule (Extended)
Why:
The left-hand rule is reserved for motor effect calculations later in the syllabus, and will give the wrong polarity for a solenoid.
Correct move:
Only use your right hand for the solenoid grip rule, fingers matching current direction, thumb pointing to the north pole.
Wrong move:
Stating induced magnetism is permanent
Why:
Induced magnetism is temporary for soft magnetic materials (e.g. pure iron) and only partially retained in hard magnetic materials (e.g. steel) after the field is removed.
Correct move:
Specify that induced magnetism only exists while the material is inside a magnetic field for pure iron, and fades over time for steel.
6. Quick Reference Cheatsheet
Concept | Core/Extended | Key Fact |
|---|---|---|
Magnetic materials | Both | Iron, cobalt, nickel, steel only |
Permanent magnet test | Both | Only repulsion is definitive |
Field line direction (outside magnet) | Both | North pole β South pole |
Induced magnet pole | Both | Opposite to the inducing magnet pole |
Magnetisation methods | Extended | Stroking, or DC current in solenoid |
Demagnetisation methods | Extended | Hammering, heating, AC current in solenoid |
Solenoid polarity rule | Extended | Right-hand grip: fingers = current, thumb = north pole |
7. Frequently Asked
Which materials are classified as magnetic for IGCSE 0625?
Only iron, cobalt, nickel, and their alloys (including steel) are magnetic at this level. All other materials (e.g. copper, aluminium, plastic, wood) are non-magnetic.
What is the only sure test for a permanent magnet?
Repulsion between like poles is the only definitive test. Attraction cannot confirm an object is a magnet, as unmagnetised magnetic materials are attracted to both poles of a magnet.
Which rule do I use to find solenoid polarity for Extended papers?
Use the right-hand grip rule: Grip the solenoid with your right hand, fingers pointing in the direction of current flow around the coil. Your outstretched thumb points to the north pole of the solenoid.
Going deeper
What's Next
Now you have mastered basic magnetism phenomena, you are ready to progress to more advanced electromagnetism topics in CIE IGCSE Physics 0625 Unit 4. The next concepts build directly on your understanding of magnetic fields and induced magnetism, including the motor effect, electromagnetic induction, and transformers, which make up a large portion of the Electricity and Magnetism unit exam weighting. Be sure to reinforce your knowledge of field line patterns and the right-hand grip rule for solenoids, as these are foundational for all subsequent electromagnetism topics. Practice structured past paper questions to test your application of these rules to exam-style scenarios, and use the cheatsheet for quick last-minute revision before your exams.