A toroid with air gap, shown in figure, has a square cross section. A long conductor carrying

Question:

A toroid with air gap, shown in figure, has a square cross section. A long conductor carrying current I2 is inserted in the air gap. If I1 = 200mA, N = 750, ?o = 10 cm, ? = 5 mm, and ?? = 1 mm, calculate(a) The force across the gap when I2 = 0 and the relative permeability of the toroid is 300.(b) The force on the conductor when I2 = 2 m A and the permeability of the toroid is infinite. Neglect fringing in the gap in both cases.