A parallel plate air capacitor has capacity $C$ farad, potential $V$ volt and energy $E$ joule. When the gap between the plates is completely filled with dielectric

Consider the situation shown in the figure. The capacitor $A$ has a charge $q$ on it whereas $B$ is uncharged. The charge appearing on the capacitor $B$ a long time after the switch is closed is 

What is the area of the plates of a $3 \mathrm{F}$ parallel plate capacitor, if the separation between the plates is $5 \mathrm{mm} ?$

In the circuit shown in the figure, the charge stored on a capacitor of capacitance $3 \mathrm{\mu F}$ is

A force $F$ acts between sodium and chlorine ions of salt (sodium chloride) when put $1 \mathrm{cm}$ apart in air. The permittivity of air and dielectric constant of water are $\varepsilon_{0}$ and $k$, respectively. When a piece of salt is put in water, electrical force acting between sodium and chlorine ions $1 \mathrm{cm}$ apart is,