The relative permeability of iron is $5500$. What will be its magnetic susceptibility?

The basic magnetization curve for a ferromagnetic material is shown in the figure. Then,the value of relative permeability is highest for the point

Susceptibility of $Mg$ at $300\, K$ is $1.2 \times 10^{-5}$. The temperature at which susceptibility will be $1.8 \times 10^{-5}$ is......$K$.

$A$ Rowland ring of mean radius $15\; cm$ has $3500$ turns of wire wound on a ferromagnetic core of relative permeability $800$. What is the magnetic field $B$ (in $T$) in the core for a magnetizing current of $1.2\; A$?

When a piece of a ferromagnetic substance is placed in a uniform magnetic field,the flux density inside it is four times the flux density away from the piece. The magnetic permeability of the material is

If $M$ is the magnetisation induced in the material,$H$ is the magnetic field intensity,and $B$ is the net magnetic field inside the material,then the correct relation between them is $(\mu_0 = \text{permeability of free space})$