Question

All magnetic materials lose their magnetic properties when
1. Cooled to very low temperature
2. Heated to high temperature
3. Kept is aluminium box
4. Kept in vacuum

Answer 1

Correct Answer - Option 2 : Heated to high temperature

• All the magnetic materials lose their magnetic properties when they are Heated.
• For every material, there is a temperature specific to it known as its Curie temperature above which the magnetic materials lose their magnetic properties.
• The Curie Temperature is a temperature at which certain magnetic
  materials undergo a sharp change in their magnetic properties.
• The Curie Temperature is named after the French physicist Pierre Curie who discovered some laws of magnetism in 1895.

Magnetic Materials & their specifications

Materials	Specifications
Iron	Used for electromagnets as well as in a permanent magnet
Iron oxides	Haematite, magnetite and ferric oxide
Nickel	Magnetic to moderate temperatures
Cobalt	Retains magnetism at high temperatures
Alloys	Certain alloys of iron, nickel or cobalt
Rare earth	Samarium and Neodymium magnets