Topic 6 Magnetism and Electromagnetism - Edexcel Physics IGCSE

Permanent Magnet

A magnet that can produce its own magnetic field and will repel and attract other magnets when in contact with them; it cannot be demagnetised.

Hard Magnetic Material

Materials that get magnetised when an external magnetic field is applied and remain magnetised permanently once the external field is removed.

Soft Magnetic Material

Materials that get magnetised when an external magnetic field is applied but lose their magnetic field (demagnetised) once the external field is removed.

Uniform Magnetic Field

Created by placing opposite poles of two magnets across from each other, resulting in magnetic field lines separated by a fixed distance.

Induced Magnetic Field

A magnetic field that is created when current flows through a wire.

Fleming’s Left Hand Rule

A rule to determine the direction of force, magnetic field, and current in a current-carrying wire.

Motor Effect

The phenomenon where a current-carrying wire in a magnetic field experiences a force that causes it to move.

Loudspeaker Function

A device that converts electrical signals into sound waves by causing a cone to vibrate through the motor effect.

Microphone Function

A device that converts sound into electrical signals by inducing a voltage in a coil of wire as it vibrates with sound pressure.

Commutator

A device used in electric motors that switches the current direction every half turn to keep the coil spinning.

Induced Voltage Factors

Factors affecting the size of induced voltage include the number of turns on the coil of wire, the strength of the magnetic field, and the speed of the magnet's movement.

Dynamo

A device that generates current by rotating a coil of wire inside a magnetic field to produce direct current (d.c.).

Alternator

A device that generates alternating current (a.c.) by rotating a coil of wire in a magnetic field and connecting it to slip rings.