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

$A$ magnetizing field of $5000 \ A/m$ produces a magnetic flux of $4 \times 10^{-5} \ Wb$ in an iron rod of cross-sectional area $0.4 \ cm^2$. The permeability of the rod in $Wb/(A \cdot m)$ is:

$A$ solenoid having $400$ turns per metre has a core of a material with relative permeability $400$. When a current of $0.5 \ A$ is passed through it,the magnetization of the core material in $Am^{-1}$ is nearly

An iron rod of cross-sectional area $0.2 \, cm^2$ is subjected to a magnetizing field intensity of $1600 \, A \cdot m^{-1}$. If the magnetic flux produced in the rod is $2.4 \times 10^{-5} \, Wb$, what is the magnetic susceptibility of the material of the rod?

Write the equation of the magnetic field obtained in the core of a solenoid in the form of $\vec{H}$ and $\vec{M}$.

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