The materials suitable for making electromagnets should have

$A$ paramagnetic salt contains $2 \times 10^{26} \, m^{-3}$ atomic dipoles. Each dipole has a magnetic moment of $1.5 \times 10^{-23} \, A \cdot m^2$. What is the saturation magnetization?

Liquid oxygen remains suspended between two pole faces of a magnet because it is

The magnetic susceptibility of ferromagnetic materials is

Given below are two statements; one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ Electromagnets are made of soft iron.
Reason $R:$ Soft iron has high permeability and low retentivity.
In the light of the above statements,choose the most appropriate answer from the options given below.

The most exotic diamagnetic materials are