An electron is trapped in a one-dimensional infinite potential well. Show that the energy difference ΔE between its quantum levels n and n + 2 is (h²/2mL²)(n + 1).
From Eq. 39-4,
E_n=\left(\frac{h^2}{8 m L^2}\right) n^2, \quad \text { for } n=1,2,3, \ldots (39-4)
E_{n+2}-E_n=\left(\frac{h^2}{8 m L^2}\right) ( n+2 )^2-\left(\frac{h^2}{8 m L^2}\right) n^2=\left(\frac{h^2}{2 m L^2}\right) ( n+1 ) .