this may help you
The Bohr model was based on the observations of the atomic emissions spectrum of the hydrogen atom. When white light is diffracted with a prism, all the colors of the visible spectrum can be seen. Each color corresponds to a specific amount of energy; however when the light given off by the hydrogen atom was passed through a prism, only certain colors of light could be seen. This led Bohr to theorize that electrons only have certain energies in an atom and they had to be in energy levels.
