Recall that unlike magnetic poles attract and like magnetic poles repel

Describe the uses of permanent and temporary magnetic materials including cobalt, steel, iron and nickel

Explain the difference between permanent and induced magnets

Describe the shape and direction of the magnetic field around bar magnets and for a uniform field, and relate the strength of the field to the concentration of lines

Describe the use of plotting compasses to show the shape and direction of the field of a magnet and the Earth’s magnetic field

Explain how the behaviour of a magnetic compass is related to evidence that the core of the Earth must be magnetic

Describe how to show that a current can create a magnetic effect around a long straight conductor, describing the shape of the magnetic field produced and relating the direction of the magnetic field to the direction of the current

Recall that the strength of the field depends on the size of the current and the distance from the long straight conductor

Explain how inside a solenoid (an example of an electromagnet) the fields from individual coils

a) add together to form a very strong almost uniform field along the centre of the solenoid
b) cancel to give a weaker field outside the solenoid

Recall that a current carrying conductor placed near a magnet experiences a force and that an equal and opposite force acts on the magnet

Explain that magnetic forces are due to interactions between magnetic fields

Recall and use Fleming’s left-hand rule to represent the relative directions of the force, the current and the magnetic field for cases where they are mutually perpendicular

Use the equation:

force on a conductor at right angles to a magnetic field carrying a current (newton, N) = magnetic flux density (tesla, T or newton per ampere metre, N/A m) × current (ampere, A) × length (metre, m)

\(F = B × I × l\)

Explain how the force on a conductor in a magnetic field is used to cause rotation in electric motors