Photoelectric Effect PDF

 When light shines on a metal surface, it can cause the emission of electrons from the surface. This effect can be explained only if light is considered to be made of photons (particles of energy). Classical wave theory predicted that increasing the intensity (brightness) of l...

 When light shines on a metal surface, it can cause the emission of electrons from the surface. This effect can be explained only if light is considered to be made of photons (particles of energy). Classical wave theory predicted that increasing the intensity (brightness) of light would provide enough energy to eject electrons, regardless of the light’s frequency. However, experiments showed that: Electrons are ejected only when the light’s frequency exceeds a certain threshold, no matter how intense the light is. Increasing the frequency of light increases the energy of the emitted electrons. According to Einstein’s explanation, when light of frequency f hits the metal, each photon transfers its energy E = hf to an electron. If the photon’s energy is greater than the work function (the minimum energy needed to eject an electron from the metal), the electron is emitted. This observation is in line with particle behavior.  For the photoelectric effect to occur, each photon must have enough energy to eject an electron from the metal surface. The minimum energy required to do this is called the work function (A) of the metal. Photoelectric Equation: The total energy of the photon is used in two ways: 1. Work Function (A): Part of the photon’s energy is used to overcome the attractive forces that bind the electron to the metal surface (this is the minimum energy needed to eject the electron). 2. Kinetic Energy (E_{el, kin}): Any energy in excess of the work function is converted into the kinetic energy of the ejected electron. This relationship is described by the equation: hf = A + E_{el, kin} where: hf is the energy of the photon, A is the work function (minimum energy required to eject the electron), E_{el, kin} is the kinetic energy of the emitted electron.