Part A
A 3s→4s
transition in sodium is not allowed by the selection rule for emission and absorption, but the 4s
state can be reached in a two-step process. What is the longest wavelength of light with which a sodium atom can reach the 4s
state after photon absorption by a ground-state atom?
Express your answer to three significant figures and include the appropriate units.
Activate to select the appropriates template from the following choices. Operate up and down arrow for selection and press enter to choose the input value typeActivate to select the appropriates symbol from the following choices. Operate up and down arrow for selection and press enter to choose the input value type

λ
=