Two capacitors,one of capacitance $C$ and the other of capacitance $C/2$,are connected in parallel to a battery of potential difference $V$. Calculate the heat produced in the connecting wires.

Initially $n$ identical capacitors are joined in parallel and are charged to potential $V$. Now they are separated and joined in series. Then

Five identical capacitors, each of capacitance $20 \mu F$, are connected to a battery of $150 V$ in the combination shown in the diagram. What is the total amount of charge stored?

The space between the plates of a parallel plate capacitor of plate area $4 \ cm^2$ and separation $d = 1.77 \ mm$ is filled with uniform dielectric materials with dielectric constants $k_1 = 5$ and $k_2 = 3$ as shown in the figure. Another capacitor of capacitance $7.5 \ pF$ is connected in parallel with it. The effective capacitance of this combination is . . . . . . $pF$. (Given $\varepsilon_0 = 8.85 \times 10^{-12} \ F/m$)

The four identical capacitors in the circuit shown below are initially uncharged. The switch is then thrown first to position $A$, and then to position $B$. After this is done:
Note: $V_{1,2,3,4}$ are the potential differences across $C_{1,2,3,4}$ and $Q_{1,2,3,4}$ are the final charges stored in $C_{1,2,3,4}$ respectively.

Twenty-seven drops of the same size are charged at $220 \, V$ each. They combine to form a bigger drop. Calculate the potential of the bigger drop (in $V$).