The following terms find importance in magnetism . Explain them
a. Magnetic permeability `(mu)`
b. Magnetic intensity (H)
c. Intensity of magnetisation (I)
d. Magnetic susceptibility `(X_m)`

Explanation

a. Magnetic permeability is the ratio of magnetic induction to magnestising field strength Permeability , `mu=B/H`
b. It is the field produced by the Amperian current. If n is the number of turns of a solenoid and I - the current through it, then H = nI. It is the magnetic field magnetises the medium and is called magnetic intensity.
c. Intensity of magnetisation is defined as the magnetic moment per unit volume.
`I=M/V,M` - magnetic moment , V - volume
d. The ratio of intensity of magnetisation to the magnetising field strength is defined as magnetic susceptibility (X)
`X=I/H`