It represents the extent to which a specimen is magnetised when placed in a magnetising field.

Or in other words the ** intensity of magnetisation **of a magnetic material is defined as the magnetic moment per unit volume of the material.

**M = Magnetic moment/volume = μM / V **…1

Let a = Uniform area of cross-section of the magnetised specimen.

l = magnetic length of the specimen.

m = strength of each pole of the specimen,

As μ_{m} = ml

and V = al

then equation (1) becomes

M = m x 2l / a x 2l

or M = m/a

thus **intensity of magnetisation **of a** **magnetic material is also defined as the pole strength per unit area of cross-section of the material.

Unit : M= magnetic moment / Volume

M= Amp.metre^{2} / metre^{3} = Am ^{-1}

These are S.I unit of M

Reference: This article is referred from my book “electrical engineering materials” having ISBN: 978-81-272-5069-0.

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