Question

can we compare electromagnetic force and gravitational force

Answer 1

yes

Answer 2

\[\frac{F_e}{F_g} = \frac{\frac{|q_1q_2|}{4 \pi \epsilon_0 r^2}}{G\frac{m_1m_2}{r^2}}\]
F_e is the force due to electromagnetic and F_g is the force due to gravity

sometimes
\[k \approx \frac{1}{4 \pi \epsilon_0} \approx 9.0 \times 10^9 Nm^2C^{-2}\]

then
\[G = 6.67 \times 10^{11} Nm^2kg^{-2}\]

Answer 3

correction
\[G = 6.67 \times 10^{-11} Nm^2kg^{-2}\]

Answer 4

I think the original question means.. are these forces comparable ?

in that case, the appropriate answer would be.. NO.. EM force is orders of magnitude stronger than gravity