Question

A curve between magnetic moment and temperature of a magnet is:

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The correct option is C

Explanation for the correct option

Option C:

1. Magnetic moment decreases with temperature because as the temperature rise, the magnetic domains gain kinetic energy which changes the orientation of the magnetic domains.
2. Due to the change in orientation or misalingment of magnetic domains under the impact of high temperature, the magnetic moment decreases with an increase in temperature.
3. On increasing the temperature, the magnetic moment decreases, and at some higher value of temperature, the magnetic moment becomes equal to zero.
4. The temperature at which magnetic moment becomes zero is called “Curie's temperature”.

Explanation for the incorrect options

Option A:

1. The graph depicts a negative (inverse) relationship between the magnetic moment and the temperature which is not the actual variation.

Option B:

1. The graph depicts that the magnetic moment is inversely proportional to the temperature which is not the actual case.
2. The graph depicts that the magnetic moment remains constant at a very high temperature which is absolutely wrong.
3. The graph has no temperature (Curie's temperature) at which the magnetic moment will become zero.

Option D:

1. The graph depicts that the magnetic moment does not change with temperature which is absolutely wrong.
2. Temeparture rise will change the oreintation of magnetic domains and consequently the magnetic moment will decrease.

Hence, option (C) is correct.