Question

A perfectly diamagnetic sphere has a small spherical cavity at its centre, which is filled with a paramagnetic substance. The whole system is placed in a uniform magnetic field $\overrightarrow{B}$. Then the field inside the paramagnetic substance is:

• A. $\overrightarrow{B}$
• B. zero
• C. Much larger than $\overrightarrow{|B|}$ and parallel to $\overrightarrow{B}$.
• D. Much larger than $\overrightarrow{|B|}$ but opposite to $\overrightarrow{B}$

Answer 1

The correct option is B zero

When a magnetic field is applied to a diamagnetic substance, it produces a magnetic field in the opposite direction, so the net magnetic field inside the cavity of the sphere will be zero.

So, the magnetic field inside the paramagnetic substance kept inside the cavity is zero.

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