The equivalent capacitance of the system shown in the following circuit is $...........\mu F$.

Four identical condensers are connected in parallel and then in series. The ratio of equivalent capacitance in series to that in parallel combination is

Find the equivalent capacitance between $A$ and $B$ of the following arrangement:

$A$ capacitor is made of a flat plate of area $A$ and the second plate has a staircase-like structure. The width of each stair is $a$ and its height is $b$. The total width of the plate is $2a$. The distance between the flat plate and the first part of the staircase is $d$. Find the capacity of the capacitor.

$A$ capacitance of $2\ \mu F$ is required in an electrical circuit across a potential difference of $1.0\ kV$. $A$ large number of $1\ \mu F$ capacitors are available which can withstand a potential difference of not more than $300\ V$. The minimum number of capacitors required to achieve this is

Find the equivalent capacitance across $A$ and $B$ in $\mu F$.