Two positive point charges, each with charge q, separated by a distance d, repel each other with a force of magnitude 20 N. What is the magnitude of the force between two positive point charges of magnitude 11.11 q, separated by a distance 2.5 d in units of N

The value is  

Explanation:

From the question we are told that

   The magnitude of the charge of each positive charge for the first case is

   The distance between the charges for the first case is  

   The  force between the charges for the first case  is  

     The magnitude of the charge of each positive charge for the second case is

     The  distance between the charge for the second case is

Generally for the first case the force between the charge is mathematically  represented as

Where k is the Coulomb constant with value  

  So  

Generally for the second  case the force between the charge is mathematically  represented as

=>      

=>      

=>      

d is the correct answer

the answer for apex is the lowest