The emission spectra of hydrogen could be explained through the Bohr atomic model. Emission means that energy must be emitted or lost. Bohr proposed the spectral lines of elements were observed as a result of the electrons moving from higher energy states to lower energy states.
The same spectral lines are always observed because the electrons are forced to these energy states that have fixed energies. Therefore, when an electron falls from a higher energy state to a lower energy state, there are a limited number of options to which the electron can fall . Each electron transition between different electron shells will cause a different wavelength of light to be emitted.
