The battery terminal voltage in Figure P20.43 is e= 9.00 V and the current /reaches half its maximum value of 2.00 A at t= 0.100 s after the switch is closed. Calculate (a) the time constant τ. (b) what is the emf across the inductor at t= 0.100 s? (c) What is the emf across the inductor in the instant after the switch is closed at t= 0?
