Answer:
The correct option is (c).
Explanation:
The electrostatic force between charges is given by :
[tex]F=k\dfrac{q_1q_2}{r^2}[/tex]
Where
r is the distance between charges
If the distance between two electric charges is tripled, r' =3r
New force becomes,
[tex]F'=k\dfrac{q_1q_2}{(3r)^2}\\\\F'=k\dfrac{q_1q_2}{9r^2}\\\\F'=\dfrac{1}{9}\times k\dfrac{q_1q_2}{r^2}\\\\F'=\dfrac{F}{9}[/tex]
So, the new force becomes 1/9 of the original force. The correct option is (c).