The volume charge density within a volume V is `rho ( r)` . What is the force on a small test charge `q_(0)` placed outside the volume having position vector `r_(0)` with respect to the same origin considered to specify the position vector of the charge distribution within the volume ?

Explanation

Force on test charge , `q_(0) E = (k Q q_(0))/(|r_0|^2) = (k. V .rho( r) .q_(0))/(|r_(0)|^(2))`