Induced Magnetism (Oxford AQA IGCSE Physics)

Induced Magnetism

• An induced magnet is a material that becomes a magnet when it is placed in a magnetic field

• Induced magnetism always causes a force of attraction

• When removed from the magnetic field, the material will lose its induced magnetism quickly

Magnetic materials

• Very few metals in the Periodic Table are magnetic

• The magnetic metals are:

  • Iron

  • Cobalt

  • Nickel

• Steel is an alloy which contains iron, so it is also magnetic

Magnetic materials

• Magnetic materials (which are not magnets) will always be attracted to the magnet, regardless of which pole is held close to it

Magnets and magnetic materials

• Bringing a material close to a known magnet will determine if the material is magnetic, non-magnetic or if it is a magnet itself

  • It is a magnet if it is repelled by the known magnet

  • It is a magnetic material if it is attracted to the known magnet

  • It is a non-magnetic material if it is neither attracted nor repelled by the known magnet

Types of magnets

• There are two types of magnets

  • Permanent magnets

  • Induced magnets

Permanent magnets

• Permanent magnets are made out of permanent magnetic materials (materials that are always magnetic), for example, steel

• A permanent magnet will produce its own magnetic field

  • It will not lose its magnetism

Induced magnets

• When a magnetic material is placed in a magnetic field, the material is temporarily turned into a magnet

  • This is called induced magnetism

• When magnetism is induced in a material:

  • One end of the material will become a north pole

  • The other end will become a south pole

• Magnetic materials will always be attracted to a permanent magnet

Induced magnetism

• In the image above:

  • The north pole of the permanent magnet induces a south pole in the magnetic material (at the end closest to the magnet)

  • The south pole of the permanent magnet induces a north pole in the magnetic material (at the end clostest to the magnet)