Bohr's third postulate
farâvas-e sevom-e Bohr
Fr.: troisième postulat de Bohr
One of the postulates used in the → Bohr model, whereby the atom emits (absorbs) a quantum of electromagnetic energy (→ photon) when the electron passes from an orbit with a greater (lesser) n value to one with a lesser (greater) value. The energy of the quantum is equal to the difference between the energies of the electron on its orbits before and after the transition or "jump": hν = ε1 - ε2, where h is the → Planck's constant and ν the frequency of the transition.