Q. In hydrogen, the transition from level 2 to level 1 has a rest wavelength of 121.6 nm. Suppose you see this line at a wavelength of 120.5 nm in Star A and 121. 2 nm in Star B. Calculate each star's speed, and state whether it is moving toward or away from us.
Q. Consider an electron in an infinite 1-D square well of width, L = 3 nm (U = 0 at the bottom).
What are the energies, E1 and E2, of the two lowest eigenstates?