Quantum light theory criticisms

Two papers by Albert Einstein ultimately led to acceptance of the idea of quantization of energy for radiation, and were central to the development of the quantum theory (ironically, in later years Einstein became the most implacable critic of this same theory). The first of these papers, in 1905, concerned the photoelectric effect. Light ejected electrons from a metallic surface if the light had a greater frequency than some threshold frequency v0 which depended on the particular metal. The kinetic energy K of the emitted electrons was proportional to the excess frequency, v — v0 (Figure 5.4). Only the number of emitted electrons, not the kinetic energy, increased as the intensity increased. 

This understanding was finally achieved in the quantum theory of 1925, which provided for the first time an adequate explanation of how matter is constructed of atoms and molecules, how atoms are constructed of nuclei and electrons, and how atoms interact with light. Each of the major developments of nineteenth-century physical science played critical roles in leading up to quantum theory. These developments included electromagnetic theory, molecular theory of matter, and statistical thermodynamics. ... 

Albert Einstein (1879-1955). .. was a German-bom theoretical physicist who is mainly renowned for his special theory of relativity and its extension to the general theory of relativity. In addition to this, he worked on statistical mechanics and quantum theory and investigated the thermal properties of light. At the beginning of his scientific career he also set important landmarks for colloid science. This applies particularly to his explanation of Brownian motion, but is also valid for the calculation of suspension viscosity as well as his theory of critical opalescence. In 1921, he was given the Nobel Prize in Physics Tor his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect . 

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