Four capacitors marked with their capacitances and breakdown voltages are connected as shown in the figure. The maximum $EMF$ of the source,so that no capacitor breaks down,is: (in $kV$)

Three uncharged capacitors of capacitances $C_1$,$C_2$,and $C_3$ are connected as shown in the figure. If $A$,$B$,and $C$ are at potentials $V_1$,$V_2$,and $V_3$ respectively,then the potential at point $O$ is:

$A$ conducting sphere of radius $a$ has charge $Q$ on it. It is enclosed by a neutral conducting concentric spherical shell having inner radius $2a$ and outer radius $3a$. Find the electrostatic energy of the system.

$n$ small drops, each of capacitance $C$, coalesce to form a single large drop. What is the ratio of the energy stored in the large drop to the energy stored in each small drop?

The potential differences that must be applied across the parallel and series combination of $3$ identical capacitors are such that the energy stored in them becomes the same. The ratio of the potential difference in the parallel combination to the series combination is:

In the circuit shown,the charge on the $5\, \mu F$ capacitor is $........\mu C$.