An Electron Is in an Infinite Square Well (A Box)

An electron is in an infinite square well (a box) that is 2.0 nm wide. The electron makes a transition from the n = 8 to the n = 7 state, what is the wavelength of the emitted photon? (h = 6.626 × 10^-34 J ∙ s, mel = 9.11 × 10^-31 kg, 1 eV = 1.60 × 10^-19)

A) 880 nm
B) 750 nm
C) 610 nm
D) 1000 nm
E) 1100 nm