The potential difference that must be applied across the series and parallel combination of $4$ identical capacitors is such that the energy stored in them becomes the same. The ratio of potential difference in series to parallel combination is

In the given capacitive network,the resultant capacitance between points $A$ and $B$ is: (in $\mu F$)

$n$ small drops of the same size are charged to $V$ volts each. If they coalesce to form a single large drop,then its potential will be:

$A$ series combination of $n_1$ capacitors,each of value $C_1$,is charged by a source of potential difference $6 \ V$. Another parallel combination of $n_2$ capacitors,each of value $C_2$,is charged by a source of potential difference $2 \ V$. The total energy of both combinations is the same. The value of $C_2$ in terms of $C_1$ is:

$A$ parallel plate capacitor of capacitance $C$ is connected to a battery and charged to a potential difference $V$. Another capacitor of capacitance $3C$ is similarly charged to a potential difference $3V$. The charging battery is then disconnected and the capacitors are connected in parallel to each other in such a way that the positive terminal of one is connected to the negative terminal of the other. The final energy of the configuration is

Three capacitors of capacitances $25 \mu F, 30 \mu F$ and $45 \mu F$ are connected in parallel to a supply of $100 \ V$. Energy stored in the above combination is $E$. When these capacitors are connected in series to the same supply,the stored energy is $\frac{9}{x} E$. The value of $x$ is . . . . . . .