The electrostatic force between two charges distance r apart in vacuum is F, The force between the same charges distance r/2 apart in a medium of dielectric constant 2 is

Options

A. F/2
B. 2F
C. F/4
D. 4F

Explanation

` because F = (1)/(4pi epsi_0 ) . (q xx q)/(r^2)`
In dielectric medium ,
`F. = (1)/(4 pi epsi_0 k) (q xx q)/( (r//2)^2)`
` = (1)/(4 pi epsi_0 xx 2) xx (q xx q)/( r^2) xx 4`
` F. = 2F`