4. Consider the circuit shown. 10 Q 20 O _/\\/\\/V\\_ 50 uF 30 Q _ 40 Q 9 V switch (a) The capacitor is fully charged. (i) Calculate the currents in all resistors. (ii) What is the charge on the capacitor? (b) After fully charging the capacitor, the switch S is now opened. After how long from the moment the switch is opened will the charge on the capacitor be equal to 1A of its initial value