The strength of the magnetic field is defined as the measure of the intensity of a magnetic field in a given area of that field. The strength of the magnetic field is measured in a unit called Gauss. The following graph depicts the strength of a magnet at different temperatures.

Observe the graph carefully.

Now, answer the following questions.

(a) At what temperature is the strength of the magnet the highest?

(b) At what temperature is the strength of the magnet the lowest?

(c) Why is the strength of the magnet reducing with increase in temperature?

(d) Is there any way to strengthen the magnet again? Why/Why not?

(a) The strength of the magnet is highest at 0°C.

(b) The strength of the magnet is lowest at 80°C.

(c) The strength of the magnet is reducing with increase in temperature because on increasing the temperature of the magnet, its molecules gain thermal energy and their kinetic energy increases which breaks the chain of the molecules and results in demagnetisation of the magnet.

(d) Yes, the magnet can be strengthen by remagnetising it via

• Single touch or double touch method (stroking with another magnet).
• Magnetic induction.