Example: If Fg and Fe are gravitational and electrostatic forces between two electrons at a distance 0.1m then Fg/Fe is in what order?
Solution: Gravitational force Fg=r2Gm2 Electrostatic force Fe=r2Kq2 FeFg=Kq2Gm2 where G=Universal gravitational constant and K=1/4πϵ0 G=6.67×10−11 and K=9×109 Mass of an electron is 9.31×10−31 and Charge of an electron is 1.6×10−19 Hence, Fg/Fe=Gm2/Kq2 is of the order of 10−11−62−9+38=10−43