Quantum Theory of Radiation

The Quantum Theory of Radiation explains how light and other electromagnetic waves are emitted or absorbed by atoms. It states that these processes occur in discrete packets called 'quanta' or photons, rather than continuously. When an atom's electron moves between energy levels, it releases or absorbs a photon with a specific energy corresponding to the difference between those levels. This quantum approach describes phenomena like blackbody radiation, atomic emission spectra, and the photoelectric effect, providing a fundamental understanding of light's particle-like behavior, which complements its wave nature in classical physics.