The Nobel Prize in Physics 1922
Niels Henrik David Bohr
Born: 7 October 1885, Copenhagen, Denmark
Died: 18 November 1962, Copenhagen, Denmark
Affiliation at the time of the award: Copenhagen University, Copenhagen, Denmark
Prize motivation: "for his services in the investigation of the structure of atoms and of the radiation emanating from them"
Field: theoretical nuclear physics
The discoveries of the electron and radioactivity at the end of the 19th century led to different models for the structure of the atom. In 1913, Niels Bohr proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities. Electrons should move around the nucleus but only in prescribed orbits. When jumping from one orbit to another with lower energy, a light quantum is emitted. Bohr's theory could explain why atoms emitted light in fixed wavelengths.