Force between two charges depends on the presence of the material between them - explain.

Explanation

From Coulomb's law in vacuum or air medium the force acting between two charges `q_(1)` and `q_(2)` separated by a distance r,
`F_(1)=(q_(1)q_(2))/(4pi in_(0)r^(2))`
Now if a material of permittivity `in` is placed in the space between the two charges then the effective force acting between the two charges,
`F_(2)=(q_(1)q_(2))/(4pi in r^(2))`
So, `F_(1)ne F_(2)`
Therefore, force acting between two charges changes in presence of material medium between them.