A separately excited d.c. motor is fed from a chopper operating at 500 Hz with a duty cycle of 50% and is drawing an average current of 10A from a 200V d.c. source. A free wheeling diode is connected across it. The motor has negligible armature resistance; a field inductance of 50mH and a torque constant of 0.5 N-m/A. determine the minimum and maximum motor current, motor back e.m.f. and the mechanical torque developed.