Co Co Ro Rotating Fixed Plate Ro 38 It is desired to keep current in discharge process of a capacitor constant For the purpose following three schemes a b and c are suggested a In this scheme after closing the switch you have to vary resistance of the rheostat The initial charge on the capacitance Co is go and range of values of resistance of the rheostat is zero to Ro Find the law R t according to which resistance of the rheostat should be changed with time b In this scheme a variable disk capacitor is connected across a fixed resistance Ro After closing the switch you have to vary the capacitance by rotating one of its plates The initial value of capacitance is Co and charge on it is qo Find the law C t according to which capacitance should be changed with time and corresponding angular velocity t of one plate relative to the other c In this scheme a variable capacitor is used in which one plate can be shifted towards or away from the other fixed plate without changing overlap area After closing the switch you have to move the movable plate The initial value of capacitance is Co and charge on it is qo Find the law C t according to which capacitance and the distance x t between the plates should be changed with time