$A$ charge $+q$ is placed somewhere inside the cavity of a thick conducting spherical shell of inner radius $R_1$ and outer radius $R_2$. $A$ charge $+Q$ is placed at a distance $r > R_2$ from the centre of the shell. Then the electric field in the hollow cavity

The intensity of the electric field at a charged point inside a hollow metallic container is ....... .

The charges on two plates of a $10\,\mu F$ capacitor are $5\,\mu C$ and $15\,\mu C$. The potential difference across the capacitor plates is........$V$.

Explain the electrostatics of conductors. Explain the effects produced inside a metallic conductor placed in an external electric field.

Two charged conducting spheres of radii $a$ and $b$ are connected to each other by a wire. What is the ratio of electric fields at the surfaces of the two spheres? Use the result obtained to explain why charge density on the sharp and pointed ends of a conductor is higher than on its flatter portions.

Assertion: $A$ positive charge particle is placed in front of a spherical uncharged conductor. The number of lines of force terminating on the sphere will be more than those emerging from it.
Reason: The surface charge density at a point on the sphere nearest to the point charge will be negative and maximum in magnitude compared to other points on the sphere.