Magnets | Physics for GCSE/IGCSE - Year 11 PDF Download

Magnetic and Non-magnetic Materials

• Iron, cobalt, and nickel are some of the few metals in the Periodic Table that exhibit magnetic properties.
• Steel, being an alloy containing iron, also possesses magnetic characteristics.
• Magnetic materials, which are not magnets themselves, will always be attracted to a magnet, irrespective of the pole being held close to them.

• When determining if a material is magnetic, one should bring it near a known magnet.
  • If the material is repelled by the magnet, it indicates that the material itself is magnetic.
  • If the material is only attracted by the magnet and not repelled, it signifies that the material is magnetic in nature.

Types of Magnets

There exist two primary categories of magnets: 

• Permanent magnets and 
• Induced magnets.

Permanent Magnets

• Permanent magnets are crafted from materials such as steel.
• These magnets generate their own magnetic fields and do not lose their magnetism over time.

Temporary (Induced) Magnets

• When a magnetic material is exposed to a magnetic field, it can temporarily acquire magnetism, a phenomenon known as induced magnetism.
• Certain objects like paperclips or steel needles can be magnetized and retain their magnetism temporarily.
• However, objects like electromagnets or transformers made from soft iron lose their magnetism once the inducing cause is removed.
• When magnetism is induced in a material, one end becomes a north pole while the other end becomes a south pole.
• Magnetic materials are always attracted to permanent magnets, resulting in the end of the material closest to the magnet acquiring the opposite pole to the magnet's closest pole.

• Once the magnetic material is taken out of the magnetic field, it rapidly loses the majority, if not all, of its magnetism.