Force between two point charges kept in a distance $d$ apart in air is $F$. If these charges are kept at the same distance in water, how does the force between them change? $\epsilon_r$ of water$=80$ ?

Ans. The force will decrease by 8 factor of 80 You May Like: Physics fulls chapter notes Class 12 Physics Test Derivation for the electric field intensity on equatorial line of Electric Dipole
Coulombs Law in Vector Form