Question

State the universal law of gravitation. The mass of the electron and proton in a Hydrogen atom is given by $9\times {10}^{-31}kg$ and $1.9\times {10}^{-27}kg$ respectively which is separated by a distance $6\times {10}^{-11}m$. Calculate the gravitational force of attraction between them? [3 MARKS]

Answer 1

Definition: 1 Mark
Problem: 2 Mark

1.The universal law of gravitation states that every object in the universe attracts every other object with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

2. Given, mass of electron, $m_e=9\times {10}^{-31}kg$ and mass of proton, $m_p=1.9\times {10}^{-27}kg$, gravitational constant, $G=6.673\times {10}^{-11}N{m}^{2}k{g}^{-2}$, and distance, $r=6\times {10}^{-11}m$
From universal law of gravitation, $F=\frac{G{m}_p{m}_e}{r^2}$
$\therefore F=\frac{6.673\times {10}^{-11}\times 1.9\times {10}^{-27}\times 9\times {10}^{-31}}{(6\times {10}^{-11}{)}^2}$
$\Rightarrow F=3.16\times {10}^{-47}N$