Charging and Discharging Capacitors 1. A capacitor of capacitance 22 HF is charged to 12 V and isolated. The charge leaks away through a resistance of 10 MS2 until the potential difference across the capacitor is 8.0 V. a) Calculate the charge that has leaked off the capacitor. b) Calculate how long the charge took to leak away. 2. The graph shows the charge on a capacitor as it discharges through a resistor. MUC 400 200 100 10 20 30 40 50 60 70 b'S a) What is the current in the resistor at t = 0? b) What is the current in the resistor at t = 15 s? c) Use the graph to find the time constant for this RC circuit. 14