Question

A powerful magnet loses its magnetism when:
1. A high mechanical stress is applied on it
2. A high electric field is applied on it
3. It is heated to very high temperature
4. It is buried inside the earth for a long time

Answer 1

Correct Answer - Option 3 : It is heated to very high temperature

The correct answer is It is heated to very high temperature.

• As the temperature increases, at a certain point called the Curie temperature, a magnet will lose its strength completely.

• Not only will a material lose its magnetism, but it will also no longer be attracted to magnets.
• Nickel has a Curie temperature of 358 Celsius (676 Fahrenheit); iron's is 770 C (1418 F).
• Once the metal cools, its ability to attract magnets returns, though its permanent magnetism becomes weak.
• In general, heat is the factor that has the most effect on permanent magnets.