A laminated soft-iron ring (μ_{r} = 1000) has a mean circumference of 800 mm and a cross-section of 500 mm². A radial air gap of 1 mm is cut in it, and it carries a 1000-turn winding. Find the current needed for an air-gap flux of 0.5 mWb, taking a leakage factor of 1.2 and a stacking factor of 0.9 (neglect fringing). (answer in A)