A ring of magnetic material has a rectangular cross-section. The inner diameter of the ring is 20 cm and the outer diameter is 25 cm, its thickness being 2 cm. An air-gap of 1 mm length is cut across the ring. The ring is wound with 500 turns and when carrying a current of 3 A produces a flux density of 1.2 T in the air-gap. Find
(a) magnetic field intensity in the magnetic material and in the air-gap.
(b) relative permeability of the magnetic material, and
(c) total reluctance of the magnetic circuit and component values.