E = hc/λ
so, if you have the energy, just find λ.
A hydrogen atom’s electron moves from the n=4 level to the n=6 level. What is the wavelength of light associated with this transition? Is the light absorbed of emitted?
2 answers
1/wavelength = R*(n/4^2 - 1/6^2) where R is Rydberg's constant. You can find that on Google. You're going from 4 to 6 so you're absorbing energy.