Permanent & Induced Magnets (OCR GCSE Physics A (Gateway)): Revision Note

Permanent & Induced Magnets

Magnetic Materials

Magnetic materials are attracted to a magnet; non-magnetic materials are not

• Very few metals in the Periodic Table are magnetic. These include:

  • Iron

  • Cobalt

  • Nickel

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

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

Magnetic materials attracted to magnets

• To test whether a material is a magnet it should be brought close to a known magnet

  • If it can be repelled by the known magnet then the material itself is a magnet

  • If it can only be attracted and not repelled then it is a magnetic material

Types of Magnets

• There are two types of magnets

  • Permanent magnets

  • Induced magnets

Permanent Magnets

• Permanent magnets are made out of permanent magnetic materials, 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 can temporarily be turned into a magnet.

  • This is called induced magnetism

• When magnetism is induced on 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

  • This means that the end of the material closest to the magnet will have the opposite pole to magnets pole closest to the material

Inducing magnetism in a magnetic material

• When the magnetic material is removed from the magnetic field it will lose most/all of its magnetism quickly