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The photon has no electric charge, [17] [18] is generally considered to have zero rest mass [19] and is a stable particle. The experimental upper limit on the photon mass [20] [21] is very small, on the order of 10 −50 kg; its lifetime would be more than 10 18 years. [22] For comparison the age of the universe is about 1.38 × 10 10 years.
Photon energy is the energy carried by a single photon. The amount of energy is directly proportional to the photon's electromagnetic frequency and thus, equivalently, is inversely proportional to the wavelength. The higher the photon's frequency, the higher its energy. Equivalently, the longer the photon's wavelength, the lower its energy.
The photon must have higher energy than the sum of the rest mass energies of an electron and positron (2 × 511 keV = 1.022 MeV, resulting in a photon wavelength of 1.2132 pm) for the production to occur. (Thus, pair production does not occur in medical X-ray imaging because these X-rays only contain ~ 150 keV.)
The energy content of this volume element at 5 km from the station is 2.1 × 10 −10 × 0.109 = 2.3 × 10 −11 J, which amounts to 3.4 × 10 14 photons per (). Since 3.4 × 10 14 > 1, quantum effects do not play a role. The waves emitted by this station are well-described by the classical limit and quantum mechanics is not needed.
Photoinduced charge separation is the process of an electron in an atom or molecule, being excited to a higher energy level by the absorption of a photon and then leaving the atom or molecule to free space, or to a nearby electron acceptor.
An obvious solution [4] is to simply add a right-handed neutrino ν R, which requires the addition of a new Dirac mass term in the Yukawa sector: = (¯) +.. This field however must be a sterile neutrino , since being right-handed it experimentally belongs to an isospin singlet ( T 3 = 0 ) and also has charge Q = 0 , implying Y W = 0 (see above ...
The photon (carrier of electromagnetism) is one of two known gauge bosons that are both believed to be massless; the other is the gluon (carrier of the strong force). The only other confirmed gauge bosons are the W and Z bosons , which are known from experiment to be extremely massive.
Thus, higher frequency photons have more energy. For example, a 10 20 Hz gamma ray photon has 10 19 times the energy of a 10 1 Hz extremely low frequency radio wave photon. The effects of EMR upon chemical compounds and biological organisms depend both upon the radiation's power and its frequency.