5.24. A Rowland ring of mean radius 15 cm has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field B in the core for a magnetising current of 1.2 A?
Radius of ring, r = 15cm = 0.15m
Number of turns in the ring, n = 3500
Relative permeability of the ferromagnetic core, = 800
Current in the Rowland ring, I = 1.2A
Magnetic Field due to a circular coil, B =
∴ B = = 4.48T
Therefore, the magnetic field B in the core for a magnetising current is 4.48 T