Question

When two point charges are a distance dd part, the electric force that each one feels from the other has magnitude F.F . In order to make this force twice as strong, the distance would have to be changed to _____

Answer 1

Answer:

In order to make this force twice as strong, F' = 2 F, the distance would have to be changed to half i.e. r' = r/2.

Explanation :

The electric force between two point charges is directly proportional to the product of charges and inversely proportional to the square of the distance between charges. It is given by :

$F=\dfrac{kq_1q_2}{r^2}$

r is the separation between charges  

$F\propto \dfrac{1}{r^2}$

$r=\sqrt{\dfrac{1}{F}}$

If F'= 2F

$r'=\dfrac{1}{\sqrt{2F} }$

In order to make this force twice as strong, F' = 2 F, the distance would have to be changed to half i.e. $r'=\dfrac{1}{\sqrt{2F} }$. Hence, this is the required solution.