A capacitor is charged to 100 V and then discharged by a 50 kΩ resistor. If the time constant of the circuit is 0.8 s, verify:
(a) The value of the capacitor,
(b) The time for the capacitor voltage to fall to 20 v,
(c) The current flowing when the capacitor has been discharging for 0.5 s
(d) The voltage drop across the resistor when the capacitor has been discharging for one second.