A coil of insulated wire of 500 turns and ofresistance 4 : is closely wound on iron ring. The ring has a mean diameter of 0. 25 m and a uniform cross-sectional area of 700 mm?. Calculate the total flux in the ring when a DC supply of 6V is applied to the ends of the winding . Assume a relative permeability of 550. N 500 D = 0.25 m V = 6 V R = 4 2 -a = 700 mm2 V -Mp=550 Fig. 1.9 Magnetic circuit