The resistor in an RC circuit has a resistance of 150 Omega.
(a) What capacitance must be used in this circuit if the time constant is to be 3.7 ms?
(b) Using the capacitance determined in part (a), calculate the current in the circuit 7.4 ms after the switch is closed. Assume that the capacitor is uncharged initially and that the emf of the battery is 9.0 V