Chemistry, asked by devilanka1112, 8 months ago

Photoelectric emission starts only if the incident radiation is having sufficient energy, that minimum energy called as:​

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Answered by AkashKumar372
3

The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, and solid state and quantum chemistry to draw inferences about the properties of atoms, molecules and solids. The effect has found use in electronic devices specialized for light detection and precisely timed electron emission.

The emission of electrons from a metal plate caused by light quanta – photons.

In classical electromagnetic theory, the photoelectric effect would be attributed to the transfer of energy from the continuous light waves to an electron. An alteration in the intensity of light would change the kinetic energy of the emitted electrons, and sufficiently dim light would result in the emission delayed by the time it would take the electrons to accumulate enough energy to leave the material. The experimental results, however, disagree with both predictions. Instead, they show that electrons are dislodged only when the light exceeds a threshold frequency. Below that threshold, no electrons are emitted from the material, regardless of the light intensity or the length of time of exposure to the light. Because a low-frequency beam at a high intensity could not build up the energy required to produce photoelectrons like it would have if light's energy was coming from a continuous wave, Einstein proposed that a beam of light is not a wave propagating through space, but a collection of discrete wave packets—photons.

Emission of conduction electrons from typical metals requires a few electron-volt (eV) light quanta, corresponding to short-wavelength visible or ultraviolet light. In extreme cases, emissions are induced with photons approaching zero energy, like in systems with negative electron affinity and the emission from excited states, or a few hundred keV photons for core electrons in elements with a high atomic number.[1] Study of the photoelectric effect led to important steps in understanding the quantum nature of light and electrons and influenced the formation of the concept of wave–particle duality.[2] Other phenomena where light affects the movement of electric charges include the photoconductive effect, the photovoltaic effect, and the photoelectrochemical effect.

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Answered by thakuruttamsing10
5

Explanation:

The minimum frequency required for the emission of electrons is called threshold frequency below which no photoelectron is emitted. This is denoted by ν

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. The minimum energy required for the emission of photoelectrons from a metal is called work function of that metal W.

W=hν

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