An iron ring of mean diameter 22 cm and cross-section 10 cm has an air gap 1 mm wide. The ring is wound uniformly with 200 turns of wire. The permeability of ring material is 1000. A flux of 0-16 mWb is required in the gap. What current should be passed through the wire? An iron ring has cross-section 3 cm and a mean diameter of 25 cm. An air gap of 0.4 mm has been made by saw cut across the section. The ring is wound with 200 turns through which a current of 2 A is passed. If the total flux is 21 x 10-5 weber, find u for iron assuming no leakage. An iron ring has a mean circumferential length of 60 cm with an air gap of 1 mm and a uniform winding of 300 turns. When a current of 1 A flows through the coil, find the flux density. The relative permeability of iron is 300. Assume = 4 x 10-7 H/m.