Rationalised 2023-24
147
Magnetism and
Matter
 EXAMPLE 5 5
Solution
(a) The field H is dependent of the material of the core, and is
H = nI = 1000 × 2 0 = 2 ×103 A/m (b) The magnetic field B is given by
B = mr m0 H
   = 400 × 4p ×10–7 (N/A2) × 2 × 103 (A/m)
   = 1