The unit of polarizability of the molecule is . . . . . . .

When a dielectric is placed in an external electric field,the electric field inside the dielectric is

$A$ dielectric slab of dielectric constant $K$ is placed between the plates of a parallel plate capacitor carrying charge $q$. The induced charge $q^{\prime}$ on the surface of the slab is given by

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.

The dielectric constant $K$ of an insulator cannot be

On what does the extent of polarization depend?