For a ferromagnetic material,the relative permeability $(\mu_r)$ versus magnetic intensity $(H)$ has the following shape:

Many of the diagrams given in the figure show magnetic field lines (thick lines in the figure) wrongly. Point out what is wrong with them. Some of them may describe electrostatic field lines correctly. Point out which ones.

Write the differences between electrostatics and magnetics.

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?

Two identical bar magnets with a length of $10 \, cm$ and a weight of $50 \, g$ are placed freely with their like poles facing each other in an inverted vertical glass tube. The upper magnet hangs in the air above the lower one such that the distance between the nearest poles of the magnets is $3 \, mm$. The pole strength of each magnet is approximately ....... $A \cdot m$.

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

List-$I$	List-$II$
$(a)$ Magnetic Induction	$(i)$ ${ML}^{2} {T}^{-2} {A}^{-1}$
$(b)$ Magnetic Flux	$(ii)$ ${M}^{0} {L}^{-1} {A}$
$(c)$ Magnetic Permeability	$(iii)$ ${MT}^{-2} {A}^{-1}$
$(d)$ Magnetization	$(iv)$ ${MLT}^{-2} {A}^{-2}$

Choose the most appropriate answer from the options given below: