On the atomic or molecular scale, why gravitational forces play no role because electric forces are enormously stronger?

Question

Answer 1

Gravity is the weakest force among all the fundamental forces. In atomic or molecular scale the gravitational attraction force is very weak. The atomic particles like protons, neutrons, electron have a mass in the order of

10^{- 27} k g

. The gravitational force is proportional to the mass of the particles.
Quantitatively let us calculate the gravitational force and the electric force between two protons.
Mass of proton,

m = 1.67 \times 10^{- 27} k g

Charge of proton,

q = 1.6 \times 10^{- 19} C

Distance between two protons is,

r = 0.12 f m = 1.2 \times 10^{- 16} m

approximately.
Gravitational force is given by,

F_{g} = G \frac{m \cdot m}{r^{2}}

(1)
Where, G is the gravitational constant having value of

6.674 \times 10^{- 11} \frac{m^{3}}{k g \cdot s^{2}}

Substituting the values in equation (1) we get,

F_{G} = 6.674 \times 10^{- 11} \times \frac{1.67 \times 10^{- 27} \times 1.67 \times 10^{- 27}}{(1.2 \times 10^{- 16})^{2}} N \Rightarrow F_{G} = 1.29 \times 10^{- 32} N

(2)
Electric force is given by,

F_{e} = k \frac{q \cdot q}{r^{2}}

(3)
Where, k is the coulomb’s constant having a value of

9 \times 10^{9} \frac{N \cdot m^{2}}{C^{2}}

Substituting the values in equation (3) we get,

F_{E} = 9 \times 10^{9} \times \frac{1.6 \times 10^{- 19} \cdot 1.6 \times 10^{- 19}}{(1.2 \times 10^{- 16})^{2}} N \Rightarrow F_{E} = 1.6 \times 10^{4} N

(4)
From the values of gravitational force and the electric force between two protons it is clear that the gravitational force is very weak in atomic scale and electric force is very strong.

On the atomic or molecular scale, why gravitational forces play no role because electric forces are enormously stronger?

Answers (1)

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