When a soap bubble is charged,its size:

Each of the $N$ small drops has a radius $r$ and is charged to a potential $V$. If these drops coalesce to form a single large drop,what is the potential of the large drop?

Three identical capacitors $C_1, C_2$ and $C_3$ have a capacitance of $1.0 \mu F$ each and they are uncharged initially. They are connected in a circuit as shown in the figure and $C_1$ is then filled completely with a dielectric material of relative permittivity $\varepsilon_r$. The cell electromotive force (emf) $V_0 = 8 \ V$. First,the switch $S_1$ is closed while the switch $S_2$ is kept open. When the capacitor $C_3$ is fully charged,$S_1$ is opened and $S_2$ is closed simultaneously. When all the capacitors reach equilibrium,the charge on $C_3$ is found to be $5 \mu C$. The value of $\varepsilon_r = . . . . $

Two identical capacitors are joined in parallel,charged to potential $V$,separated and then connected in series,$i.e.$,the positive plate of one is connected to the negative plate of the other. Then

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

Four capacitors and a battery are connected as shown. The potential drop across the $7 \mu F$ capacitor is $6 \ V$. Then the: