The magnetic susceptibility of iron is 5499 . The relative permeability of iron will be

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

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 $\mathrm{Am}^{-1}$ is nearly

The materials having negative magnetic susceptibility are