The ratio of electric force and gravitational force between a proton
and an electron is
2
39
2 4
10
e
p
k e G
m m
≅
×
7 Superposition Principle: The principle is based on the property that the
forces with which two charges attract or repel each other are not
affected by the presence of a third (or more) additional charge(s) For
an assembly of charges q1, q2, q3,