The Photoelectric Effect: The Limitations of Classical Physics

One of the first physical phenomena to demonstrate the limitations of classical physics was the photoelectric effect. This experiment illuminates a metal surface surrounded by a vacuum; as a result, some “electrons” are emitted, micro-particles with a negative electric charge. The result was surprising: the energy emitted by these electrons from the metal surface was not proportional to the intensity of the light, but only to its frequency (or wavelength). As noted earlier, the intensity of the light – the amount of energy carried by the wave – was proportional to the square of the amplitude of the wave’s electric field, so the energy of the electrons emitted was expected to be proportional to the intensity of the light they emit. There are three ways in which this can happen: either the energy carried by each electron will increase, or the number will increase, or both will happen. He found that the second possibility is what actually happens, the more electrons are emitted, but the energy of each electron remains constant. Whether the falling light is weak or strong, the energy of each electron is equal to hf, i.e., the product of the frequency of light multiplied by the value of the general physical constant h, known as Planck's constant. More: https://braheen.com/publications/فيزياء-الكوانتم-حقيقة-أم-خيال — Source: Published on Facebook's "Braheen Center" page