Q.

If two charges q1 and q2 are separated with distance 'd' and placed in a medium of dielectric constant K, what will be the equivalent distance between the charges in air for the same electrostatic force                      [2023]

1 Kd  
2 1.5dK  
3 2dK  
4 dK  

Ans.

(4)

F=1(4πε0)q1q2kd2 (in medium)

Fair=14πε0q1q2d2

F=Fair

q1q24πε0kd2=q1q24πε0d2

  d'=dk