Question

A water drop of radius 10^-5cm is given a charge 1.6× 10^-19c.If it floats in a electric field,what is the intensity of the electric field?

Answer 1

some important formula used here

mass = volume * density

density $=\frac43\pi r^3$

Force by electric field = Force of gravity

$1.6\times10^{-19}\times E=\frac{4\pi\times(10^{-7})^3}{3}\times1000\times10$

$E=2.61\times10^{2}$ volt/ m