Find the ratio of the electric and gravitational forces between two protons.
Given:
Mass of proton, 
Charge on proton, 
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Formula used:
By Coulomb’s law, the electric force is given by:
Where ϵ0 is the permittivity of free space
k is the electrostatic constant
q1 and q2 are the magnitude of charges
r is the distance of separation between the charges
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Formula used:
By Newton’s law of gravitation, the gravitational force is given by:
Where G is the Gravitational constant
m1 and m2 are the magnitude of charges
r is the distance of separation between the masses
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The electric force is given by:
The gravitational force is given by:
Dividing (2) by (1), we get
Hence the ratio of electric force to gravitational force between two protons is about 1.23 × 1036.