Physics - Elecrostatics Question with Solution | TestHub

A charged oil drop is suspended in a uniform field of $3\times 10^4\mathrm{V}/\mathrm{m}$ so that it neither falls nor rises. The charge on the drop will be (take the mass of the charge $=9.9\times 10^{-15}\mathrm{kg}$ and $\mathrm{g}=$ $10\mathrm{m}/{\mathrm{s}}^2$ )