Question

A block of certain material is placed in a uniform magnetic field. The distribution of magnetic field lines around the block is as shown in the diagram. If the temperature of the block is increased, the number of magnetic field lines passing through the block will,

• A. increase
• B. decrease
• C. may increase or decrease depending on the final temperature
• D. remain same

Answer 1

The correct option is B decrease

In external magnetic field, some of the magnetic field lines are passing through the block, which means that the block is made of paramagnetic material.

As the temperature is increased, the susceptibility of paramagnetic material goes on decreasing.

Hence, as the temperature is increased, the magnetization of the block will decrease.

Therefore, the number of magnetic field lines passing through the block will go on decreasing, as the temperature is increased.

Hence, option $\left(B\right)$ is the correct answer.