$A$ potential difference of $300\, V$ is applied to a combination of $2.0\,\mu F$ and $8.0\,\mu F$ capacitors connected in series. The charge on the $2.0\,\mu F$ capacitor is

The combined capacity of the parallel combination of two capacitors is four times their combined capacity when connected in series. This means that:

The combination of capacitors with $C_1 = 3\,\mu F$,$C_2 = 4\,\mu F$,and $C_3 = 2\,\mu F$ is charged by connecting $A$ and $B$ to a battery. Consider the following statements:
$I.$ Energy stored in $C_1$ $=$ Energy stored in $C_2$ $+$ Energy stored in $C_3$
$II.$ Charge on $C_1$ $=$ Charge on $C_2$ $+$ Charge on $C_3$
$III.$ Potential drop across $C_1$ $=$ Potential drop across $C_2$ $=$ Potential drop across $C_3$
Which of these is/are correct?

Three parallel plate air capacitors are connected in parallel. Each capacitor has plate area $A/3$ and separation between the plates is $d$, $2d$, and $3d$ respectively. The equivalent capacity of the combination is ($\epsilon_0$ is the permittivity of free space).

What is the equivalent capacitance between the points $P$ and $Q$ in the combination of capacitors shown in the figure (in $\mu F$)?

$A$ parallel combination of three capacitors of capacities $2C$,$C$,and $C/2$ is connected across a $10 \ V$ battery. All the capacitors are fully charged to charges $Q_1$,$Q_2$,and $Q_3$ respectively. The ratio $Q_1: Q_2: Q_3$ is