$A$ 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?

Match List-$I$ with List-$II$.

List-$I$ (Material)	List-$II$ (Susceptibility $(\chi)$)
$A$. Diamagnetic	$I$. $\chi=0$
$B$. Ferromagnetic	$II$. $0 > \chi \geq -1$
$C$. Paramagnetic	$III$. $\chi >> 1$
$D$. Non-magnetic	$IV$. $0 < \chi < \varepsilon$ (a small positive number)

Choose the correct answer from the options given below:

The Curie temperature $T_{C}$ represents:

Alnico is an alloy of which metals? Explain.

The materials having negative magnetic susceptibility are

Electrical resistance of certain materials,known as superconductors,changes abruptly from a nonzero value to zero as their temperature is lowered below a critical temperature $T_c(0)$. An interesting property of superconductors is that their critical temperature becomes smaller than $T_c(0)$ if they are placed in a magnetic field,i.e.,the critical temperature $T_c(B)$ is a function of the magnetic field strength $B$. The dependence of $T_c(B)$ on $B$ is shown in the figure.
$1.$ In the graphs below,the resistance $R$ of a superconductor is shown as a function of its temperature $T$ for two different magnetic fields $B_1$ (solid line) and $B_2$ (dashed line). If $B_2 > B_1$,which of the following graphs shows the correct variation of $R$ with $T$ in these fields?
$2.$ $A$ superconductor has $T_c(0) = 100 \ K$. When a magnetic field of $7.5 \ T$ is applied,its $T_c$ decreases to $75 \ K$. For this material,one can definitely say that when:
$(A)$ $B = 5 \ T, T_c(B) = 80 \ K$
$(B)$ $B = 5 \ T, 75 \ K < T_c(B) < 100 \ K$
$(C)$ $B = 10 \ T, 75 \ K < T_c < 100 \ K$
$(D)$ $B = 10 \ T, T_c = 70 \ K$
Give the answer for questions $1$ and $2$.