Two point charges `q_(1) , q_(2)` initially at infinity are brought one by one points `P_1` and `P_2` specified by position vectors `r_1` and `r_2` , relative to some origin . What is the potential energy of this energy configuration ?

Explanation

The potential energy of the given charge configuration is `U = (1)/(4 pi in_(0)) * (q_(1) q_(2))/(|vecr_(2) - vecr_(1)|)`