Two conducting spheres $A$ and $B$ have radii $1 \, mm$ and $2 \, mm$ respectively and are charged. They are placed at a distance of $5 \, cm$. When they are connected by a conducting wire,the ratio of the electric field intensities on their surfaces at equilibrium 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........$V$.

Two conductors of the same shape and size,one of copper and the other of aluminium (which is less conducting),are placed in a uniform electric field. What can be said about the charge induced in the aluminium conductor?

Given below are two statements $:$ one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A) :$ The outer body of an aircraft is made of metal which protects persons sitting inside from lightning strikes.
Reason $(R) :$ The electric field inside the cavity enclosed by a conductor is zero.
In the light of the above statements,choose the most appropriate answer from the options given below.

Can there be a potential difference between two adjacent conductors carrying the same charge?

$A$ hollow metal sphere of radius $R$ is charged with a charge $Q$. The electric potential and intensity inside the sphere are respectively