Effect of Medium #8211; When a dielectric medium is completely filled by the two charges, rearrangement of the charges inside the dielectric medium takes place and the force between the charges decreases by a factor of K, known as dielectric constant or relative permittivity (ε<sub>r/gt;subgt;) of the medium (relative means with respect to free space). (K = F<sub>0</sub>/F<sub>m</sub>) [where, F<sub>0</sub> = 1/4πε<sub>0</sub> q<sub>1</sub> q<sub>2</sub>/r<sup>2</sup>, F<sub>m</sub> = 1/4πε<sub>m</sub> q<sub>1</sub>q<sub>2</sub>/r<sup>2</sup>]