Magnetism (Edexcel IGCSE Physics)

The law of magnetism

Poles of a magnet

• The ends of a magnet are called poles

• Magnets have two poles: a north and a south

Poles of a Magnet

The law of magnetism

• When two magnets are held close together, there will be an attractive or repulsive force between the magnets depending on how they are arranged:

Opposite poles attract; like poles repel

• The law of magnetism states that:

  • Two like poles repel (e.g. S and S or N and N)

  • Two opposite poles attract (e.g. S and N)

• The attraction or repulsion between two magnetic poles occurs due to the magnetic force

Magnetic materials

• Magnetic materials can be soft or hard

• Magnetically soft materials (e.g. iron):

  • Are easy to magnetise

  • Easily lose their magnetism (temporarily magnetised)

• Magnetically hard materials (e.g. steel):

  • Are difficult to magnetise

  • Do not easily lose their magnetism (permanently magnetised)

• Permanent magnets are made out of magnetically hard materials

• Electromagnets are made out of magnetically soft materials

  • This means that electromagnets can be made magnetic or non-magnetic as an when required

A steel pin will be attracted when an electromagnet switches on but not when it switches off. It is always attracted to a permanent magnet