In the network shown, each capacitor has capacitance is 2μF.Then the charge flown through the battery after the switch S is closed, is

Initial charge stored in the system Qi=C2×E=22×12 μC=12 μC.Final charge stored in the system,Qf=C×2C(C+2C)×E=2CE3=2×2×123 μC=16 μC.Charge flown through the system,∆Q=(16-12) μC =4 μC.