Five indentical capacitor plates, each of area $A,$ are arranged such that adjacent plates are at distance $d$ apart. The plates are connected to a source of $emf$ $V$ as shown in fig. Then the charges $1$ and $4$ are, respectively :-

The equivalent capacitance of the combinatio shown in Figure is

Four identical capacitors are connected in series with a battery of $emf$ $10\,V$. The point $X$ is earthed, then the potential of point $A$ is…..$V$

A parallel plate capacitor of capacitance $C$ is connected to a battery and is charged to a potential difference $V$ . Another capacitor of capacitance $2C$ is similarly charged to a potential difference $2V$ . The charging battery is now disconnected and the capacitors are connect in parallel to each other in such a way that the positive terminal of one is connected to the negative terminal of the other. The final energy of  the configuration is

Two opposite and equal charges $4 \times {10^{ – 8}}\, coulomb$ when placed $2 \times {10^{ – 2}}\,cm$ away, form a dipole. If this dipole is placed in an external electric field $4 \times 10^8\, newton / coulomb$ , the value of maximum torque and the work done in rotating it through $180^o$ will be