What are the energies of the first three energy levels of an electron confined in a one-dimensional box of length 0.70 nm?

How much energy must the electron lose to jump from the n=2 energy level to the n=1 energy level?

Suppose that an electron can jump from the n=2 level to the n=1 level by emitting a photon of light. If energy is conserved, what must the photon's wavelength be? Give your answer in nm