2007 Q26 Capacitance

The solution from today's past paper on capacitance. Some of you are still struggling with resistors in capacitive circuits. Remember that at the moment when the switch in such a circuit is closed, the capacitor is fully discharged so all the voltage of the supply is across the resistor and the current in the resistor is at a maximum. This current can also be called the charging current.

Unless the capacitor is fully charged or fully discharged then the resistor and the capacitor will each have a share of the voltage. Always read the question carefully so that you know whether the stated voltage is across the capacitor or the resistor.