The magnetic susceptibility is defined as:

The magnetic susceptibility of a material of a rod is $349$ and the permeability of vacuum $\mu_0$ is $4 \pi \times 10^{-7} \ SI$ units. The absolute permeability of the material of the rod in $SI$ units is:

$A$ domain in ferromagnetic iron is in the form of a cube of side length $1\; \mu m$. Estimate the number of iron atoms in the domain and the maximum possible dipole moment and magnetisation of the domain. The molecular mass of iron is $55\; g/mol$ and its density is $7.9\; g/cm^3$. Assume that each iron atom has a dipole moment of $9.27 \times 10^{-24}\; A m^2$.

The dipole moment of each molecule of a paramagnetic gas is $1.5 \times 10^{-23} \, A \cdot m^2$. The temperature of the gas is $27 \, ^\circ C$ and the number of molecules per unit volume is $2 \times 10^{26} \, m^{-3}$. The maximum possible intensity of magnetization in the gas will be:

If the magnetizing field on a ferromagnetic material is increased,its permeability

$A$ domain in a ferromagnetic substance is in the form of a cube of side length $2 \mu m$. It contains $4 \times 10^{14}$ atoms and each atomic dipole has a moment of $16 \times 10^{-24} \text{ A m}^2$. The magnetization of the domain is . . . . . . .