$A$ bar magnet has length $3 \,cm$, cross-sectional area $2 \,cm^2$ and magnetic moment $3 \,Am^2$. The intensity of magnetization of the bar magnet 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 magnetic induction and the intensity of the magnetic field inside an iron core of an electromagnet are $1 \ Wb \ m^{-2}$ and $150 \ A \ m^{-1}$, respectively. The relative permeability of iron is $(\mu_0 = 4 \pi \times 10^{-7} \ H \ m^{-1})$.

$A$ material of $0.25 \ cm^2$ cross-sectional area is placed in a magnetic field of strength $(H) 1000 \ Am^{-1}$. Then,the magnetic flux produced is (Susceptibility of material is $313$) (Permeability of free space,$\mu_0 = 4 \pi \times 10^{-7} \ Hm^{-1}$)

Oersted is a unit of

$A$ domain in a ferromagnetic substance is in the form of a cube of side $1 \mu m$. If it contains $8 \times 10^{10}$ atoms and each atomic dipole has a dipole moment of $9 \times 10^{-24} \ A \cdot m^{2}$,then the magnetisation of the domain is