$${(8\pi^2)(9,11 \times 10^{–31}\, \mathrm{kg})(6,8\, \mathrm{eV} – 5,1\, \mathrm{eV}) \\ (1,60 \times 10^{–19}\, \mathrm{J/eV}) = 1,956 \times 10^{–47}\, \mathrm{J \cdot kg}}$$