A DC voltage source provides a voltage V = 12.0 V and isconnected to a resistor of resistance R = 150 ? and an idealinductor with inductance L, forming the circuit shown in thefigure. (Figure 1) For a long time, the switch has been in theposition shown, so that a constant current has been built up in thecircuit by the voltage source. At t=0 the switch is thrown open toremove the voltage source from the circuit. At time t after t=0,the current through the inductor and the voltage across theinductor are given by, respectively, I(t) and V(t).

If the inductor has inductance 60.0 mH , what is the timeconstant ? for this circuit?