An oil drop of radius 2 mm with a density 3 g cm^-3 is held stationary under a constant electric field 3.55 × 10^5 V m^-1 in the Millikan's oil drop…

An oil drop of radius $\displaystyle 2$ mm with a density $\displaystyle 3 \mathrm{~g} \mathrm{~cm}^{-3}$ is held stationary under a constant electric field $\displaystyle 3.55 \times 10^5 \mathrm{~V} \mathrm{~m}^{-1}$ in the Millikan's oil drop experiment. What is the number of excess electrons that the oil drop will possess ? Consider $\displaystyle \mathrm{g}=9.81 \mathrm{~m} / \mathrm{s}^2$