In a bulk material, these moments add up vectorially and they
can give a net magnetic moment which is non-zero 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