How will you connect four capacitors,each of capacitance $4 \mu F$,to obtain an equivalent capacitance of $1.6 \mu F$?

$A$ $100 \, V$ battery is connected across the series combination of two capacitors of $4 \, \mu F$ and $8 \, \mu F$. The energy stored in the series combination is

In the given figure,the equivalent capacitance between points $A$ and $B$ is (in $C$)

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).

Four capacitors with capacitances $C_1 = 1\ C$,$C_2 = 2\ C$,$C_3 = 3\ C$,and $C_4 = 4\ C$ are connected to a battery of potential $V$ as shown in the figure. Find the ratio of charges on $C_2$ and $C_4$.

Which quantity is same in each capacitor of series connection?