We define
magnetisation M of a sample to be equal to its net magnetic moment per
unit volume:
M= mVnet
(5 7)
M is a vector with dimensions L–1 A and is measured in a units of A m–1 Consider a long solenoid of n turns per unit length and carrying a
current I The magnetic field in the interior of the solenoid was shown to
be given by
B0 = m0 nI
(5