A magnetic material acquires magnetism in an applied magnetic field. The magnetization is due to the rotation of magnetic dipoles of atoms or molecules of the substance in the direction of the applied magnetic field. The magnetic dipole moment per unit volume of the material is called intensity of magnetization or simply magnetization (M).
The magnetic flux density or magnetic induction (B) inside the material is directly proportional to the applied magnetic field (H) on the material.
i.e., B ∝ H (or) B = μH = μ0μrH _____ (7.4)
where μ = magnetic permeability of the material, Equation (7.4) can be written as: ...