Three capacitors of capacitance $3\,\mu F$,$10\,\mu F$,and $15\,\mu F$ are connected in series to a voltage source of $100\,V$. The charge on $15\,\mu F$ is ....... $\mu C$.

Three capacitors each of capacitance $9 \;pF$ are connected in series.
$(a)$ What is the total capacitance of the combination?
$(b)$ What is the potential difference across each capacitor if the combination is connected to a $120 \;V$ supply?

Two capacitors $C_1 = 2 \ \mu F$ and $C_2 = 3 \ \mu F$ are connected in series between points $A$ and $C$. The potential at point $A$ is $40 \ V$ and the potential at point $C$ is $10 \ V$. Find the potential at point $B$ (between the two capacitors). (in $V$)

In the figure below, the capacitance of each capacitor is $3 \mu F$. The effective capacitance between $A$ and $B$ is:

Two capacitors are charged by a battery of $E$ volts as shown in the figure. What will be the ratio of the charges on these capacitors,$Q_1/Q_2$?

$A$ network of four capacitors with capacitances $C_1 = C$,$C_2 = 2C$,$C_3 = 3C$,and $C_4 = 4C$ is connected to a battery as shown in the figure. The ratio of the charges on $C_2$ and $C_4$ is