The load on a basic chopper circuit consists of a series combination of R=9.6 Ohm , L=12 mH, and a back emf Ec=20V. The period of the chopper is T=0.25ms. The dc supply voltage is 220 V. a) Find the critical value of the on-time for which the minimum value of the load current is zero. b) Find the value of the maximum load current corresponding to the conditions of part (a). c) Assume Ton=0.5T, determine the maximum value of the instantaneous load current