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ถามโจทย์ปัญหา => ถามโจทย์ปัญหาฟิสิกส์อื่นๆ => Topic started by: peem on May 16, 2010, 10:13:47 PM

Title: เเกมมา โฟตอน
Post by: peem on May 16, 2010, 10:13:47 PM

Title: Re: เเกมมา โฟตอน
Post by: ปิยพงษ์ - Head Admin on May 17, 2010, 06:38:27 AM

จาก Wikipedia

"In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic "unit" of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force. The effects of this force are easily observable at both the microscopic and macroscopic level, because the photon has no rest mass; this allows for interactions at long distances. Like all elementary particles, photons are governed by quantum mechanics and will exhibit wave-particle duality — they exhibit properties of both waves and particles. For example, a single photon may be refracted by a lens or exhibit wave interference with itself, but also act as a particle giving a definite result when quantitative momentum is measured."

"Gamma radiation also known as gamma rays is electromagnetic radiation of high frequency (very short wavelength). They are produced by sub-atomic particle interactions such as electron-positron annihilation, neutral pion decay, radioactive decay, fusion, fission or inverse Compton scattering in astrophysical processes. Gamma rays typically have frequencies above 1019 Hz, and therefore have energies above 100 keV and wavelength less than 10 picometers, often smaller than an atom. Gamma radioactive decay photons commonly have energies of a few hundred keV, and are almost always less than 10 MeV in energy."

"In physics, a photon is usually denoted by the symbol γ (the Greek letter gamma). This symbol for the photon probably derives from gamma rays, which were discovered and named in 1900 by Paul Villard and shown to be a form of electromagnetic radiation in 1914 by Ernest Rutherford and Edward Andrade. In chemistry and optical engineering, photons are usually symbolized by hν, the energy of a photon, where h is Planck's constant and the Greek letter ν (nu) is the photon's frequency. Much less commonly, the photon can be symbolized by hf, where its frequency is denoted by f."