In the following figure, a rectangular iron core is shown where a 3 mm of air-gap is cut in the core. The mean length of the magnetic path is 150 cm with cross-section of (3 cm × 3 cm). Two coils are present with number of turns as N_a = 600 and N_b = 500, and carry 2 A and 1 A respectively. What is the flux in the air gap? Assume the relative permeability μ_r =1400.