A photon is an elementary particle, the quantum of light and all other forms of electromagnetic radiation.
Report Abuse. In quantum physics, the photon (from Greek φως, phōs, meaning light) is the quantum of the electromagnetic field(light). That is to say, an electromagnetic field is made up of many photons. The term photon was coined by Gilbert Lewis in 1926. The photon is one of the elementary particles. In quantum physics, the photon is the quantum of the electromagnetic field(light). That is to say, an electromagnetic field is made up of many photons. Source(s): http://en.wikipedia.org/wiki/Photon. Gurpreet · 10 years ago. According to the photon theory of light, photons. . . As mentioned above, light has properties of both a wave and a particle. This was an astounding discovery and is certainly outside the realm of how we normally perceive things. Billiard balls act as particles, while oceans act as waves. Photons are spin-1 particles (making them bosons), with a spin axis that is parallel to the direction of travel (either forward or backward, depending on whether it's a left-hand or right-hand photon). This feature is what allows for polarization of light. A photon is an elementary particle, the quantum of light and all other forms of electromagnetic radiation. It is the force carrier for the electromagnetic force, even when static via virtual photons. A photon is massless, has no electric charge, and is stable. A photon has two possible polarization states. In the momentum representation, which is preferred in quantum field theory, a photon is described by its wave vector, which determines its wavelength λ and its direction of propagation. Particle-like behavior is not restricted to the visible-light portion of the electromagnetic radiation spectrum, however. Radio waves, infrared rays, visible light,ultraviolet rays, X rays, and gamma rays all consist of photons, each of which contains a particular amount of energy that depends on the wavelength. e = hc / s. where h is Planck's constant (approximately equal to6.626 times 10 -34 joule-second) and c is the speed of electromagnetic-field propagation in the medium in question (approximately 2.998 times 10 8 meters per second in a vacuum). A photon is the quantum of electromagnetic radiation that describes the particle properties of an electromagnetic wave. The energy of a photon is given by the equation E = hf, where E is energy, h is Planck's constant, and f is frequency. Planck's constant = 6.63 * 10^-34 joule-second (J-s). The total energy in an electromagnetic wave is the sum of the energies of each photon in the wave. The energy of a photon is so small that we usually measure it in electronvolts (eV). One eV is the potential energy of each electron in a 1-volt battery. Definition of a Photon. A photon is the quantum of electromagnetic radiation. The term quantum is the smallest elemental unit of a quantity, or the smallest discrete amount of something. Thus, one quantum of electromagnetic energy is called a photon. Planck's constant = 6.63 * 10^-34 joule-second (J-s). The total energy in an electromagnetic wave is the sum of the energies of each photon in the wave. The energy of a photon is so small that we usually measure it in electronvolts (eV). One eV is the potential energy of each electron in a 1-volt battery. n. The elementary particle of light and other electromagnetic radiation; the quantum of electromagnetic energy. The photon is the massless, neutral vector boson that mediates electromagnetic interactions. pho·ton′ic adj. photon. n. 1. (Atomic Physics) a quantum of electromagnetic radiation, regarded as a particle with zero rest mass and charge, unit spin, and energy equal to the product of the frequency of the radiation and the Planck constant. To put it simply photons are the fundamental particle of light. They have a unique property in that they are both a particle and a wave. This is what allows photons unique properties like refraction and diffusion.  Basic Properties of Photons. 1  move at a constant velocity, c = 2.9979 x 10 8 m/s (i.e. the speed of light), in free space. 2  have zero mass and rest energy. 3  carry energy and momentum, which are also related to the frequency nu and wavelength lamdba of the electromagnetic wave by E = h nu and p = h / lambda. Photons are spin-1 particles (making them bosons), with a spin axis that is parallel to the direction of travel (either forward or backward, depending on whether it's a left-hand or right-hand photon). This feature is what allows for polarization of light. The energy of a photon of frequency is given by. where h is Planck's constant. Because the energy of photons is directly proportional to their frequency, low-energy photons have low frequencies, while high-energy photons have high frequencies. 
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what is a photon