Physics

Problem

Which one of the following expressions gives the electric potential energy

U

of two point charges

q_1

and

q_2

separated by a distance

r

in vacuum? a)

U=\dfrac{1}{4\pi\varepsilon_0}\,\dfrac{|q_1 q_2|}{r}

U=\dfrac{1}{8\pi\varepsilon_0}\,\dfrac{q_1 q_2}{r}

U=\dfrac{1}{4\pi\varepsilon_0}\,\dfrac{(q_1+q_2)^2}{r}

U=\dfrac{1}{4\pi\varepsilon_0}\,\dfrac{q_1 q_2}{r}