Using hydrogen in his experiments Bohr showed that an electron spins around the atom nuclei at a specific/discrete radii (orbital levels). Electrons at every orbital level spin at a discrete angular momentum and energy. When the electron moves one orbital level down, it releases a photon of energy specific to the jump (that is, of a particular spectrum that is unique to the atom). When the electron goes up an orbital level, energy (of a specific spectrum) is absorbed. This emission and absorption spectrum varies across atoms and is calculated as (delta)E = hf where;
<span>The understanding of atomic emission spectrum led to the development of the atomic theory is explained by Niels Bohr in his atomic model theory for hydrogen atom based on the quantum theory. He explained the atomic structure in which the hydrogen atom consists of a proton as a nucleus, with a single electron moving in distinct circular orbits around it, and each orbit has a quantized energy state.
According to Bohr atomic theory, a light quantum is emitted when an electron jumps from a higher energy orbit to a lower energy orbit. He has also explained the reason that why do the atoms emit light in fixed wavelengths.</span>
