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 8)
If the interior of the solenoid is filled with a material with non-zero
magnetisation, the field inside the solenoid will be greater than B0 The
net B field in the interior of the solenoid may be expressed as
B = B0 + Bm
(5