Consider the circuit given below. Here the switch S is closed at
time t =0, in order to charge an initially uncharged capacitor C,
through a resistor R. The capacitance of the capacitor is C = 15 x
10-6 F and the resistance of the resistor is R = 30.0 Ω. At what
time is the potential across the capacitor is equal to the
potential across the resistor?