Answer:
16
Explanation:
The magnitude of the electrostatic force between two charged particles is given by
[tex]F=\frac{kq_1 q_2}{r^2}[/tex]
where
k is the Coulomb's constant
q1, q2 are the charges of the two particles
r is the separation between the particles
In this problem, the initial force between the particles is F.
Later, the distance between the two particles is increased by four, so
r' = 4r
So, the new force between the particles will be
[tex]F'=\frac{kq_1 q_2}{(4r)^2}=\frac{kq_1 q_2}{16r^2}=\frac{1}{16}F[/tex]
So, the new force decreases by a factor of 16.