Allright, when I say what is electric potential energy, someone will say it is kq1q2/r ... This answer doesn't satisfy me because what I am searching for is this.. Electric potential energy denoted by U is the work done by an external force to bring a charge from infinity to zero" ...That is why keeping two positive charges, the force done by hand would be positive, therefore U possessed by the test charge realtive to infinity is positive. Likewise, I am asking my new question now... WHAT IS ELECTIC POTENTIAL... I don't need formulas, I need the qualitative meaning! ... Thanks for anyone woshares his ideas.. I owe a lot to those people!