The effect of the charge
has been incorporated in the existence of the electric field We obtain the
force F exerted by a charge Q on a charge q, as
F
r
=
41
0
2
πε
rQq
ˆ
(1 7)
Note that the charge q also exerts an equal and opposite force on the
charge Q The electrostatic force between the charges Q and q can be
looked upon as an interaction between charge q and the electric field of
Q and vice versa