Is it possible to have an arrangement of two point charges separated by finite distances such that the electric potential energy of the arrangement is the same as if the two charges were infinitely far apart? What if there are three charges?

Explanation

`U_oo=0`
`U_r=1/(4piepsilon_0).(q_1q_2)/r` (for two charges)
`U_r!=U_oo`
`For r!=oo`
`U-r=1/(4piepsilon_0)[(q_1q_2)/r_12+(q_2q_3)/r_23+(q_3q_1)/r_31)]`
Now `U_r` can be equal to `U_oo` for finite value of r.