Magnetic Fields

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The basics

The Invisible Force Field

📖 The Invisible Force Field

You can't see a magnetic field, but it's very real — it can move objects without touching them! Every magnet creates a region of space around it where magnetic materials experience a force. The field exists whether or not there's anything there to feel it. Earth itself is a giant magnet — that's how compasses work. Birds may even navigate using Earth's magnetic field. From fridge magnets to MRI scanners, magnetism shapes our world in invisible but powerful ways.

Like poles?: Repel

Hotspot diagram

An electromagnet — click each component to see how it works and how to make it stronger.

A 3D render of an electromagnet: copper coil on iron core, battery connected, cyan field lines arcing around, iron nails attracted to the pole. Click each part to learn how electromagnets work.

1
Coil (solenoid) —
2
Soft iron core —
3
Field lines —

Figure 1: An electromagnet — click each component to see how it works and how to make it stronger.

Key terms

Physics glossary

Like poles?: Repel
Unlike poles?: Attract

Spotlight

Magnetic Fields and Field Lines

A magnetic field is a region in which a magnetic material experiences a force. We represent this using field lines — imaginary lines that show the direction and strength of the field.

Exam tip

Earn the mark scheme marks

🧠 Memory Aid

Poles rule: "Like poles Repel — unlike poles attract." Think of people: similar personalities (like poles) clash and push each other away; opposites attract.

Field line rules — NACC:

North to South (direction outside)
Arrows show N-pole movement
Closer = stronger
Can't cross

Electromagnet strength — CIT:

Current (increase it)
Iron core (add one)
Turns (add more)

Soft iron vs steel: "Soft iron = soft memory — forgets magnetism instantly. Steel = steel trap — holds magnetism forever."

Now try it yourself

Quiz · Question 1 of 14

What happens when two like magnetic poles (e.g. north and north) are brought close together?

Tap an answer to check it

This topic in real past papers

Every real exam question we've found on magnetic fields, with a full worked answer.

Edexcel Paper 2

Tracing the field around a current-carrying wire, comparing a bar magnet's field with a uniform field, and sketching the Earth's own magnetic field

14 marks

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