From the following, what charges can be present on oil drops in Millikan's experiment

(Here e is the electronic charge)

The charge on electron was discovered by

Cathode rays are produced when the pressure is of the order of

In Milikan’s experiment, an oil drop having charge $q$ gets stationary on applying a potential difference $V$ in between two plates separated by a distance $‘d’$. The weight of the drop is

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