When a piece of polythene is rubbed with wool,a negative charge of $4 \times 10^{-7} \ C$ is developed on the polythene. The number of electrons transferred from wool to polythene is $\left[e = 1.6 \times 10^{-19} \ C\right]$.

Assertion $(A)$: Half of the charge of an electron does not exist. Reason $(R)$: Electric charge is quantized.

Select the correct statement about electric charge.

There are two metallic spheres of same radii,but one is solid and the other is hollow. Then:

Number of electrons in one coulomb of charge will be

While doing his experiment,Millikan one day observed the following charges on a single drop:
$(i)$ $6.563 \times 10^{-19} \ C$
$(ii)$ $8.204 \times 10^{-19} \ C$
$(iii)$ $11.50 \times 10^{-19} \ C$
$(iv)$ $13.13 \times 10^{-19} \ C$
$(v)$ $16.48 \times 10^{-19} \ C$
$(vi)$ $18.09 \times 10^{-19} \ C$
From this data,the value of the elementary charge $(e)$ was found to be: