1. The problem statement, all variables and given/known data Between which energy levels are the photons in this line transitioning? Wavelength= 660 * 10^-9 m Change in energy = 3.01 * 10^-9 A. 4 and 2 B. 3 and 2 C. 3 and 1 D. 2 and 1 2. Relevant equations [PLAIN]http://upload.wikimedia.org/math/0/e/f/0ef5602ad67cd5ef919e2ead1a173040.png, [Broken] E is energy, h is Planck's constant (6.63 x 10-34 J s), f is frequency, c is the speed of light (3.00* 10^8 m/s), and λ is wavelength. 3. The attempt at a solution Ok, so I could solve for frequency using either of these equations with the given info, but how would that help me determine which energy levels the photons are transitioning from? Answer: The photon with the lowest energy and longest wavelength corresponds to the 3 to 2 transition. (there were 3 other lines of given data, the line in this question was the lowest energy and longest wavelength) How can you tell that the photon with the lowest energy and longest wavelength corresponds to the 3 to 2 transition?