Physics

Problem

Which of the following expressions gives the electric potential energy

U

of a system consisting of two point charges

q_1

and

q_2

separated by a distance

r

in vacuum? a)

U=\dfrac{k\left(q_1^{2}+q_2^{2}\right)}{r}

U=-\dfrac{k q_1 q_2}{r}

U=\dfrac{k q_1 q_2}{r}

U=\dfrac{k q_1 q_2}{2r}