The separation between an electron and a proton in a hydrogen atom is 0.83 Å. Find the electric force of attraction between them.

$33.39 × 10^{-9} N$

The correct answer is Option (3) → $33.39 × 10^{-9} N$

Using Coloumbs law,

Force, $F=\frac{1}{4πε_0}×\frac{c^2}{r^2}$

$=\frac{1}{4π(8.85×10^{-12})}×\frac{(1.6×10^{-19})^2}{(0.83×10^{-10})^2}$

$=\frac{9×10^9}{6.889×10^{-21}}×2.56×10^{-38}$

$≃33.39×10^{-9} N$