The magnetic property of a magnetic substance is associated with

Which of the following curves represents the variation of magnetic moment $(M)$ with temperature $(T)$ for a ferromagnetic material?

$A$ thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on,the diamagnetic rod is pushed up,out of the horizontal magnetic field. Hence,the rod gains gravitational potential energy. The work required to do this comes from:

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$. Consider a ferromagnetic material:
Assertion $(A)$: The individual atoms in a ferromagnetic material possess a magnetic dipole moment and interact with one another in such a way that they spontaneously align themselves forming domains.
Reason $(R)$: At high enough temperature, the domain structure of a ferromagnetic material disintegrates. Thus, magnetization will disappear at a high enough temperature known as the Curie temperature.
In the light of the above statements, choose the correct answer from the options given below:

$A$ sample of paramagnetic salt contains $20 \times 10^{24}$ atomic dipoles each of dipole moment $1.5 \times 10^{-23} \ J \ T^{-1}$. The sample is placed under a homogeneous magnetic field of $0.84 \ T$,and cooled to a temperature of $4.2 \ K$. The degree of magnetic saturation achieved is equal to $15 \%$. What is the total dipole moment (approximate) of the sample for a magnetic field of $0.98 \ T$ and a temperature of $2.8 \ K$? (Assume Curie's law).

If a diamagnetic substance is brought near the north or south pole of a bar magnet,it is: