If the size of the charge value is tripled for both of two point charges maintained at a constant separation,the mutual force between them will be changed by what factor?

Question

Quizplus · Accepted Answer

According to Coulomb's law, the force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of their separation distance. 
So, if the charge value is tripled for both charges, the force between them will become nine times (3x3) stronger. Therefore, the mutual force between them will be changed by a factor of 9 or 9.0. Hence, the correct answer is (A).

If the Size of the Charge Value Is Tripled for Both