1: Part a) For the circuit given below, switch stays in closed position for long enough time before it opens at time t = 0 sec. Determine an expression for ??(?), ??? ??(?) for t>0. Also, draw and label the graph for ??(?) as a function of time (t). [10 marks] V1 = (2 times the last digit of your student number) in V. If your student # is 123456789, then V1=18 V If your student # is 987654321, then V1 = 2 V But, if last digit of your student number is 0, V1 = (2*10) Volts. If your student # is 123456780, then V1 = 20 V Figure 1 a: RL circuit with DC input