Three capacitors of capacity $C_1, C_2, C_3$ are connected in series. Their total capacity will be

The effective capacitance between the points $P$ and $Q$ of the arrangement shown in the figure is......$\mu F$

Three capacitors each of capacitance $1\,\mu F$ are connected in parallel. To this combination,a fourth capacitor of capacitance $1\,\mu F$ is connected in series. The resultant capacitance of the system is.......$\mu F$

Two condensers of capacities $C$ and $2C$ are connected in parallel and then in series with a $3^{\text{rd}}$ condenser of capacity $3C$. The combination is charged to $V$ volts. The charge on the condenser of capacity $C$ is:

Three capacitances of capacity $10\,\mu F$,$5\,\mu F$,and $5\,\mu F$ are connected in parallel. The total capacity will be ........ $\mu F$.

Four metallic plates, each with a surface area of one side $A$, are placed at a distance $d$ from each other. The plates are connected as shown in the figure. The capacitance of the system between $a$ and $b$ is