A hollow metal sphere of radius $5\,cm$ is charged such that the potential on its surface is $10\,V$. The potential at a distance of $2\,cm$ from the centre of the sphere.......$V$

A $2\,\mu F$ capacitor is charged as shown in the figure. The percentage of its stored energy dissipated after the switch $S$ is turned to position $2$, is.....$\%$

A thin spherical conducting shell of radius $R$ has charge $q$. Another charge $Q$ is placed at the centre of the shell. The electrostatic potential at a point $P$ at a distance $R/2$ from the centre of the shell is

In an adjoining figure three capacitors $C_1,\,C_2$ and $C_3$ are joined to a battery. The correct condition will be (Symbols have their usual meanings)

Two spherical conductors $B$ and $C$ having equal radii and carrying equal charges in  them repel each other with a force $F$ when kept apart at some some distance. $A$ third  spherical conductor having same radius as that of $B$ but uncharged, is brought in contact with $B$, then brought in contact with $C$ and finally removed away from both.  The new force of repulsion between $B$ and $C$ is-

The plates of a parallel plate capacitor are charged up to $100\, volt$ . A $2\, mm$ thick plate is inserted between the plates, then to maintain the same potential difference, the distance between the capacitor plates is increased by $1.6\, mm$ . The dielectric constant of the plate is