The vehicles carrying inflammable fluids usually have metallic chains touching the ground:

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:

Why can metal rods not be charged by holding them in hands?

Five balls numbered $1$ to $5$ are suspended using separate threads. Pairs $(1, 2)$,$(2, 4)$,and $(4, 1)$ show electrostatic attraction,while pairs $(2, 3)$ and $(4, 5)$ show repulsion. Therefore,ball $1$ must be:

Faraday's law of electrolysis indirectly shows:

In a Millikan's oil drop experiment,the charge on an oil drop is calculated to be $6.35 \times 10^{-19} \ C$. The number of excess electrons on the drop is: