A mild steel closed magnetic circuit has a mean length of 75mm and a cross-sectional area of 320.2mm2.
A current of 0.40 a flows in a coil wound uniformly around the circuit and the flux produced is 200µWb.
If the relative permeability of the steel at this value of current is 400 find
(a) The reluctance of the material and
(b) The number of turns of the coil.