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On The Constitution of Atoms and Molecules
Bohr turned to Planck's quantum theory to explain the stability of most atoms. He found that the ratio of energy in electrons and the frequency of their orbits around the nucleus were equal to Planck's constant. Bohr suggested the revolutionary idea that electrons jump between energy levels (orbits) in a quantum fashion. When an atom absorbs or gives off energy, the electron jumps to higher or lower orbits. -
The Spectra of Hydrogen
Niels Bohr proposed a theory for the hydrogen atom, based on quantum theory that some physical quantities only take discrete values. Electrons move around a nucleus, but only in prescribed orbits, and if electrons jump to a lower energy orbit, the difference is sent out as radiation. Bohr's model explained why atoms only emit light of fixed wavelengths, and later incorporated the theories on light quanta. -
Transmutation of Atomic Nuclei by Impact of Material Particles
In 1936, Bohr pointed out that in nuclear processes the smallness of the region in which interactions take place, as well as the strength of these interactions, justify the transition processes to be described more in a classical way than in the case of atoms. Nuclear transmutation is the conversion of one nuclide into another. The extreme facility of energy exchanges between the densely packed particles in atomic nuclei plays a decisive role in determining the course of nuclear transmutations -
The Discussion of Nuclear Fission
Niel Bohr announced the splitting of the uranium atom during the Fifth Washington Conference at the George Washington University. Fission, with the release of two hundred million electron volts of energy, pave the beginning of the atomic age. Two of Bohr's colleagues at Copenhagen, Otto Hahn, and Fritz Strassmann reported that they had discovered the element barium after bombarding uranium with neutrons. Bohr accompanied John Wheeler, a theoretical physicist at Princeton.