Magnetism is everywhere around us - from the magnets on... Show more
Physics101 views·Updated May 22, 2026·5 pagesMagnetism and Electromagnetism Explained
Charlotte@charlotte26
1 / 5
1
of 5
Magnetism Basics
Think of magnets as having two distinct personalities at opposite ends - the north pole and south pole. Just like people, opposites attract whilst similar personalities clash.
Like poles repel whilst unlike poles attract . The magnetic force is strongest right at the poles and works as a non-contact force - meaning magnets don't need to touch to affect each other.
Only certain metals respond to magnets: iron, steel, cobalt and nickel. These are called magnetic materials, and they're the reason your steel scissors stick to a magnet but your plastic ruler doesn't.
Key Tip: The magnetic force gets weaker as you move further from the poles - that's why magnets work best when they're close together.
2
of 5
Types of Magnets
Permanent magnets are like that reliable friend who never changes. Made from magnetic materials, they always maintain their magnetic properties and constantly produce their own magnetic field.
Induced magnets are more like fair-weather friends - they only become magnetic when placed near another magnet. Remove the magnetic field, and they quickly lose their magnetism.
This difference explains why some materials become temporarily magnetic when near a magnet but return to normal when moved away.
Remember: Permanent magnets keep their magnetism; induced magnets only "borrow" it temporarily.
3
of 5
Magnetic Fields and Testing
To test if something is truly magnetic, try this: a permanent magnet can both attract AND repel other magnets, but it can only attract magnetic materials. If it repels, you've definitely got a magnet on your hands.
Magnetic fields are invisible areas around magnets where their force operates. We can detect these using a magnetic compass - essentially a tiny bar magnet that rotates to point towards magnetic north.
Electromagnets (also called solenoids) are brilliant because you can switch them on and off. They're made by wrapping wire in a coil and passing current through it. Add an iron core, and you've massively boosted the magnetic field strength.
Cool Fact: Earth itself is like a giant magnet with an iron and nickel core, which is why compasses work!
4
of 5
The Motor Effect and Electric Motors
The motor effect might sound complicated, but it's actually quite straightforward - when you pass current through a wire in a magnetic field, the wire experiences a force that pushes it at right angles.
This force follows the equation: force = magnetic flux density × current × length. More current or stronger magnetic field equals more force.
Electric motors use this principle brilliantly. A coil of wire sits in a magnetic field, and when current flows through it, the coil rotates. The clever bit is the commutator - it switches the current direction every half turn, keeping the motor spinning in the same direction.
Real-World Connection: This same principle powers everything from your electric toothbrush to electric cars!
5
of 5
Fleming's Left Hand Rule and Transformers
Fleming's left hand rule is your go-to memory aid for working out directions in the motor effect. Your thumb shows movement direction, forefinger shows the magnetic field (north to south), and your second finger shows current direction (positive to negative).
The force is strongest when current flows at 90° to the magnetic field. If they're parallel, there's no motor effect at all.
Transformers are incredibly useful devices that change voltage in alternating current. They use two coils wound around an iron core - when alternating current flows through the primary coil, it creates a changing magnetic field that induces a different voltage in the secondary coil.
Essential Knowledge: Transformers only work with alternating current because they need the constantly changing magnetic field to function.
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Physics101 views·Updated May 22, 2026·5 pagesMagnetism and Electromagnetism Explained
Charlotte@charlotte26
Magnetism is everywhere around us - from the magnets on your fridge to the motors in your phone's vibration. Understanding how magnets work and how electricity can create magnetic fields opens up a whole world of physics that powers most... Show more
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Magnetism Basics
Think of magnets as having two distinct personalities at opposite ends - the north pole and south pole. Just like people, opposites attract whilst similar personalities clash.
Like poles repel whilst unlike poles attract . The magnetic force is strongest right at the poles and works as a non-contact force - meaning magnets don't need to touch to affect each other.
Only certain metals respond to magnets: iron, steel, cobalt and nickel. These are called magnetic materials, and they're the reason your steel scissors stick to a magnet but your plastic ruler doesn't.
Key Tip: The magnetic force gets weaker as you move further from the poles - that's why magnets work best when they're close together.
2
of 5Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Types of Magnets
Permanent magnets are like that reliable friend who never changes. Made from magnetic materials, they always maintain their magnetic properties and constantly produce their own magnetic field.
Induced magnets are more like fair-weather friends - they only become magnetic when placed near another magnet. Remove the magnetic field, and they quickly lose their magnetism.
This difference explains why some materials become temporarily magnetic when near a magnet but return to normal when moved away.
Remember: Permanent magnets keep their magnetism; induced magnets only "borrow" it temporarily.
3
of 5Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Magnetic Fields and Testing
To test if something is truly magnetic, try this: a permanent magnet can both attract AND repel other magnets, but it can only attract magnetic materials. If it repels, you've definitely got a magnet on your hands.
Magnetic fields are invisible areas around magnets where their force operates. We can detect these using a magnetic compass - essentially a tiny bar magnet that rotates to point towards magnetic north.
Electromagnets (also called solenoids) are brilliant because you can switch them on and off. They're made by wrapping wire in a coil and passing current through it. Add an iron core, and you've massively boosted the magnetic field strength.
Cool Fact: Earth itself is like a giant magnet with an iron and nickel core, which is why compasses work!
4
of 5Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
The Motor Effect and Electric Motors
The motor effect might sound complicated, but it's actually quite straightforward - when you pass current through a wire in a magnetic field, the wire experiences a force that pushes it at right angles.
This force follows the equation: force = magnetic flux density × current × length. More current or stronger magnetic field equals more force.
Electric motors use this principle brilliantly. A coil of wire sits in a magnetic field, and when current flows through it, the coil rotates. The clever bit is the commutator - it switches the current direction every half turn, keeping the motor spinning in the same direction.
Real-World Connection: This same principle powers everything from your electric toothbrush to electric cars!
5
of 5Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Fleming's Left Hand Rule and Transformers
Fleming's left hand rule is your go-to memory aid for working out directions in the motor effect. Your thumb shows movement direction, forefinger shows the magnetic field (north to south), and your second finger shows current direction (positive to negative).
The force is strongest when current flows at 90° to the magnetic field. If they're parallel, there's no motor effect at all.
Transformers are incredibly useful devices that change voltage in alternating current. They use two coils wound around an iron core - when alternating current flows through the primary coil, it creates a changing magnetic field that induces a different voltage in the secondary coil.
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