Everything on the GCSE Physics Magnetism & Fields poster is written out below, section by section. Use it to search the sheet, copy parts into your own notes, or check a fact quickly.
Magnets
A magnet has two poles: north (N) and south (S). Unlike poles attract each other, whilst like poles repel.
Only magnetic materials such as iron, steel, nickel and cobalt can be magnetised or attracted to a magnet.
Magnetic field lines
A magnetic field is the region around a magnet where a magnetic force is felt. We represent it using field lines.
- Field lines go from north to south.
- The direction of the lines shows the direction of the force on a north pole placed in the field.
- Where the lines are closer together, the field is stronger.
Magnetic fields from electric currents
A current-carrying wire produces a magnetic field made up of concentric circles around the wire.
The right-hand grip rule
Use the right-hand grip rule to find the direction of the field around a straight wire:
- Point your thumb in the direction of the current.
- Your curled fingers show the direction of the magnetic field.
Solenoids
A solenoid is a coil of wire carrying a current. The magnetic field around a solenoid is similar to the field around a bar magnet, with a distinct north and south pole at each end.
Electromagnets
An electromagnet is a solenoid with a soft iron core inside. It is a temporary magnet that can be switched on and off by controlling the current.
An electromagnet becomes stronger when you:
- increase the number of turns of wire on the coil
- increase the current
- place an iron core inside the coil
Key idea
- Electric currents can create magnetic fields.
- Magnets and fields can act on each other.