Two capacitors of same capacity are first joined in series and then in parallel. The ratio of resultant capacity in series to that in parallel combination will be

The equivalent capacitance between $A$ and $B$ is......$\mu F$.

$A$ circuit has a section $AB$ as shown in the figure. If the potential difference between points $A$ and $B$ is $V$ volts,then the potential difference across $C_1$ is

Capacitors of $C, 2C, 4C, \dots, \infty$ are connected in parallel. What will be their equivalent capacitance?

Ten capacitors are connected in parallel to a battery of $V$ volts. If all capacitors are disconnected from the battery and then connected in series,what will be the voltage across the combination in terms of $V$ (in $V$)?

Two capacitors of capacitances $1 \ \mu F$ and $2 \ \mu F$ can separately withstand potentials of $6 \ kV$ and $4 \ kV$ respectively. The total potential they together can withstand when they are connected in series is (in $kV$)