Diamagnetism

Q.

Explain the curie-Weiss theory in detail.

Q. 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 $B$. Then the field inside the paramagnetic substance is:

1. more than $|\overrightarrow{B}|$ and parallel to $\overrightarrow{B}$.
2. Zero
3. less than $|\overrightarrow{B}|$ and parallel to $\overrightarrow{B}$.
4. less than $|\overrightarrow{B}|$ and anti-parallel to $\overrightarrow{B}$.

Q. Following plots show magnetization $\left(M\right)$ vs magnetizing field $\left(H\right)$ and magnetic susceptibility $\left(\chi \right)$ vs temperature $\left(T\right)$ graphs :


Which of the following combinations will be represented by a diamagnetic material?

1. (b), (d)
2. (a), (c)
3. (b), (c)
4. (a), (d)