Quantum (Lat. Quantum - So much)

Quantum is an elementary unit of radiant energy. The quantum has no electric charge and its mass is very small. The energy of a quantum is inversely related to the wavelength of radiation: the shorter the wavelength, the greater the energy of the quantum.

Quantum theory explains the interaction of electromagnetic radiation and matter based on the concept of discrete energy. According to this theory, the energy of the electromagnetic field is emitted and absorbed not continuously, but in separate portions - quanta. The quantum size is proportional to the radiation frequency.

The concept of a quantum made it possible to explain a number of phenomena that are incomprehensible from the point of view of classical physics, in particular the photoelectric effect. The quantum nature of radiation underlies the operation of lasers, solar cells and other quantum devices. Thus, the discovery of quanta became one of the most important achievements in physics of the 20th century.