The region around a magnet where a force acts on another magnet or on a magnetic material (iron, steel, cobalt, and nickel) is called the magnetic field.
The following is true of magnetic fields:
- The force between a magnet and a magnetic material is always one of attraction.
- The strength of the magnetic field depends on the distance from the magnet.
- The field is strongest at the poles of the magnet.
- The direction of the magnetic field at any point is given by the direction of the force that would act on another north pole placed at that point.
- The direction of a magnetic field line is from the north (seeking) pole of a magnet to the south (seeking) pole of the magnet.
To help with analyses of electromagnetism, have a go at making your own and investigating the science below.
When a current flows through a conducting wire a magnetic field is produced around the wire.
The strength of the magnetic field depends on:
- the current through the wire and
- the distance from the wire.
Shaping a wire to form a solenoid increases the strength of the magnetic field created by a current through the wire.
An electromagnet is a solenoid with an iron core.
To make the electromagnet stronger:
- Increase more number of turns to the coil.
- Increase the flow of current through the coil.
- Wrap the coil around the iron piece.
- Increase in current or voltage.
Electromagnets have many uses. Below shows the use of an electromagnet in an electric bell:
Self-asses with GCSE exam questions.
Don't forget to check your answers.