The following figure represents the magnetic circuit of a primitive relay. The coil has 500 turns and the mean core path is lc = 360 mm. When the air gap lengths are 1.5 mm each, a flux density of 0.8 tesla is required to actuate the relay. The core is cast steel. (a) Find current in the coil. (b) Compute the values of permeability and relative permeability of the core. (c) If the air gap is zero, find the current in the coil for the same flux density (0.8 T) in the core. Come Mean path