![]() ![]() The photoelectric effect can occur even with the lowest frequency light called the threshold frequency. Threshold frequency: V o= (eV o)/h = work function/Planck's constant In order to emit more electrons, the light source must be brightened to increase intensity, which still maintains frequency of light and same energy, but increases the number of photons. However, if the photon reached the threshold frequency it could cause one electron to be emitted. He concluded that if the threshold frequency of the metal was greater than the frequency of the photon, then the photon will have no effect when it bombards the metal surface. Increase frequency->Increases kinetic energy of electronsĮinstein explanation was that light had the characteristic of a particle (photon) with the photon energy of E=hv. Increase brightness (maintains frequency and energy)->Increases Intensity (increases#of phot ons)->Increases # of electrons emitted ![]() But it doesn't matter how much energy is increased or how much you increase the amplitude when it comes to trying to emit electrons from a metallic surface. The energy output will be greater and when this happens the amplitude of the light wave increases. So by increasing brightness, intensity increases, and so does energy released. In other words, the intensity can be described as the brightness from a source of light. The amount of electrons ejected is determined by the intensity of the incident light, however, the frequency of the light effects the kinetic energies of the emitted electrons. This process holds true when the incident light has a higher frequency than a certain threshold value. ![]() The photoelectric effect phenomenon that electrons are emitted when light strikes the surface of metals was discovered by Heinrich Hertz in 1888. Planck's equation: E=hv Planck's constant: h=6.626x10 -34 Js Einstein's idea was revolutionary because he brought a new perspective at looking at light not only as a wave, but as a particle. This equation states that the frequency and energy of a quantum of electromagnetic radiation are proportional. Lewis), were "particles of light" that had similar energy to that of Planck's equation. In 1905 he declared that photons (named by G.N. \)Īlbert Einstein showed that the dependence on frequency could not be justified by the classical wave theory alone, so he provided a particle perspective. ![]()
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