Answer to Question #168551 in Electricity and Magnetism for Ralph Jefferson V. Silos

Question

The Electron and the proton have opposite signs, so the electric force between the particles is attractive. The ratio F electric/Fg= 2×10^39; hence , the gravitational force between the particles is negligible compared with the electric force between them. Because each force is inversely proportional to distance squared, their ratio is independent of the distance between the two particles

Answer 1

Answer

According to gravitational law

Gravitational force is given

$F_g=\frac{Gmm'}{r^2}$

In other hand electrosratic force is given by

$F_e=\frac{kqq'}{r^2}$

Now according to question

$F_e/F_g=\frac{kqq'}{Gmm'}$

Which is independent of distance between them.

$F_e/F_g=\frac{kqq'}{Gmm'}$

$=\frac{9\times10^9\times1.6\times10^{-19}\times1.6\times10^{-19}}{6.67\times10^{-11}\times9.1\times10^{-31}\times1.67\times10^{-27}}$

=$2\times10^{39}$

Hence proved.