BITSAT 2015 Paper

From the figure. The net charge shared between the two capacitors Q' = $Q_2-Q_2$ = 4CV - CV = 3CV $Q_1$ = $C_1V_1$ = CV $Q_2$ = $C_2V_2$ = (2C) (2C) = 4CV The two capacitors will have some potential, say V'. The net capacitance of the parallel combination of the two capacitors C' = $C_1+C_2$ = C + 2C + 3C The potential of the capacitors V' = $\frac{Q'}{C'}$ = $\frac{3CV}{3C}$ = V The electrostatic energy of the capacitors E' = $\frac{1}{2}C'V'^2$ = $\frac{1}{3}(3C)V^2$ = $\frac{3}{2}CV^2$