The electric force acting between two point charges kept at a certain distance in vacuum is $16 \ N$. If the same two charges are kept at the same distance in a medium of dielectric constant $8$,the electric force acting between them is . . . . . . .

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Net dipole moment of a polar dielectric substance is zero in the absence of an external electric field.
Reason $(R)$: In the absence of an external electric field,the different permanent dipoles of a polar dielectric substance are oriented in random directions.
In the light of the above statements,choose the most appropriate answer from the options given below.

Choose the correct relation between polarisation $P$ and electric susceptibility $\chi_{e}$ of a dielectric material. ($E =$ electric field)

Explain the polarization of a polar molecule in a uniform electric field.

If the dielectric constant and dielectric strength are denoted by $k$ and $x$ respectively,then a material suitable for use as a dielectric in a capacitor must have

Select the '$WRONG$' statement about polar molecules.