The difference between equivalent capacitances of two identical capacitors connected in parallel to that in series is $6\mu \mathrm{F}$. The value of capacitance of each capacitors is

The equivalent capacitance between $A$ and $B$ is,

For the arrangement of capacitors as shown in the circuit, the effective capacitance between point $A$ and $B$ is (capacitance of each capacitor is $4\mu F)$

In figure, charge on the capacitor is plotted against potential difference across the capacitor. The capacitance and energy stored in the capacitor are respectively.