Effective capacitance of parallel combination of two capacitors C_1 and C_2 is 10 μ F. When these capacitors are individually connected to a voltage…

Effective capacitance of parallel combination of two capacitors $\displaystyle \mathrm{C}_1$ and $\displaystyle \mathrm{C}_2$ is $\displaystyle 10 \mu \mathrm{~F}$. When these capacitors are individually connected to a voltage source of $\displaystyle 1$ V, the energy stored in the capacitor $\displaystyle C_2$ is $\displaystyle 4$ times that of $\displaystyle C_1$. If these capacitors are connected in series, their effective capacitance will be :