Electric potential energy or electric field potential refers to the amount of potential energy per unit of charge and it's measured in joules/coulomb. The electric potential energy of q in the potential of Q₁ can be obtained with the potential energy formula. Here q_N (8.8541878176e-12 F/m) is the charge, ε₀ is permittivity and r_N is the separation between the two point charges. Substitute the given values into the formula to find the electric potential energy of system of charges.