Two short bar magnets of length $1 \ cm$ each have magnetic moments $1.20 \ Am^2$ and $1.00 \ Am^2$ respectively. They are placed on a horizontal table parallel to each other with their $N$ poles pointing towards the South. They have a common magnetic equator and are separated by a distance of $20.0 \ cm$. The value of the resultant horizontal magnetic induction at the mid-point $O$ of the line joining their centres is close to (Horizontal component of Earth's magnetic induction is $3.6 \times 10^{-5} \ Wb/m^2$)

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

List-$I$	List-$II$
$(A)$ Magnetic induction	$(I)$ $\text{Ampere meter}^2$
$(B)$ Magnetic intensity	$(II)$ $\text{Weber}$
$(C)$ Magnetic flux	$(III)$ $\text{Gauss}$
$(D)$ Magnetic moment	$(IV)$ $\text{Ampere/meter}$

Choose the correct answer from the options given below:

$A$ bar magnet has a total length $2l = 20$ units and the field point $P$ is at a distance $d = 10$ units from the centre of the magnet. If the relative uncertainty of length measurement is $1\%$,then the uncertainty of the magnetic field at point $P$ is

Assertion: We cannot think of a magnetic field configuration with three poles.
Reason: $A$ bar magnet does exert a torque on itself due to its own field.

Some physical quantities are given in List-$I$ and their related units are given in List-$II$. Match the correct pairs.

List-$I$	List-$II$
$(A)$ Magnetic field intensity	$(i)$ $Wb$
$(B)$ Magnetic flux	(ii) $Wb \cdot m^{-2}$
$(C)$ Magnetic pole strength	(iii) $A \cdot m$
$(D)$ Magnetic induction	(iv) $A \cdot m^{-1}$

Answer the following questions:
$(a)$ Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled?
$(b)$ Why is diamagnetism, in contrast, almost independent of temperature?
$(c)$ If a toroid uses bismuth for its core, will the field in the core be (slightly) greater or (slightly) less than when the core is empty?
$(d)$ Is the permeability of a ferromagnetic material independent of the magnetic field? If not, is it more for lower or higher fields?
$(e)$ Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at every point.) Why?
$(f)$ Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisation of a ferromagnet?