photon

1. The quantum of electromagnetic energy, regarded as a discrete particle having zero mass, no electric charge, and an indefinitely long lifetime.
2. A unit of retinal illumination, equal to the amount of light that reaches the retina through 1 square millimeter of pupil area from a surface having a brightness of 1 candela per square meter.

An entity that can be loosely described as a quantum of energy of electromagnetic radiation. According to classical electromagnetic theory, an electromagnetic wave can transfer arbitrarily small amounts of energy to matter. According to the quantum theory of radiation, however, the energy is transferred in discrete amounts. The energy of a photon is the product of Planck's constant and the frequency of the electromagnetic field. In addition to energy, the photon possesses momentum and also possesses angular momentum corresponding to a spin of unity. The interaction of radiation with matter involves the absorption, scattering, and emission of photons. Consequently, the energy interchange is inherently quantized. See also Angular momentum; Energy; Momentum; Spin (quantum mechanics).

For many purposes, the photon behaves like a particle of zero rest mass moving at the speed of light. The particlelike nature of the photon is vividly exhibited by the photoelectric effect, predicted by A. Einstein, in which light is absorbed in a metal, causing electrons to be ejected. An electron absorbs a photon, gaining its energy. In leaving the metal, it loses energy because of interactions with the surface; the energy loss equals the product of the so-called work function of the surface and the charge of the electron. The final kinetic energy of the electron therefore equals the energy of the incident photon minus this energy loss. See also Photoemission.

A second demonstration of the particlelike behavior of photons is provided by the scattering of an x-ray photon from an electron bound in an atom. The electron recoils because of the momentum of the photon, thereby gaining energy. As a result, the frequency, and hence the wavelength of the scattered x-ray, is altered. If the x-ray is scattered through a certain angle, the wavelength is shifted by an amount determined by this scattering angle and the mass of an electron, according to the laws of conservation of energy and momentum. See also Compton effect.

From a more fundamental view, the photon is the quantum of excitation of a single mode of a radiation field. The dynamical equations for the electric and magnetic energy in such a field are identical to those of a harmonic oscillator. According to quantum theory, the allowed energies of a harmonic oscillator are given by E = (j + ½)hf, where h is Planck's constant, f is the frequency of the oscillator, and the quantum number j = 0, 1, 2, …, describes the state of excitation of the oscillator. This quantum relation was first postulated by M. Planck for the material oscillators in the walls of a thermal enclosure in order to obtain the correct form for the density of radiation in a thermal field, but it was quickly applied by Einstein to describe the state of the radiation field itself. In this picture, j describes the number of photons in the field. See also Harmonic oscillator; Quantum electrodynamics; Quantum mechanics.

Dealing with light (photons). See photon and photonics.

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A bullet or quantum of electromagnetic radiant energy emitted and propagated from various types of radiation sources. The term should not be used alone but should be qualified by terms that will clarify the type of energy (e.g., light photon, x-ray photon).

For more information on photon, visit Britannica.com.

The quantum, or bundle of energy, in which light and other forms of electromagnetic radiation are emitted. (See atom.)

A particle (quantum) of radiant energy.

• x-ray p. — a particle of x-ray energy.

Discrete portion of electromagnetic energy. A small packet of light.

Photon: The Idiot Adventures
Genre	Action, Adventure, Comedy
Original video animation
Director	Koji Masunari
Studio	AIC
Released	1997
Episodes	6
Manga
Author	Hiroshi Kanno
Original run	1997 – 1998
Volumes	3
Anime and Manga Portal

Photon: The Idiot Adventures is a 6 episode anime OVA series by Koji Masunari. The main character, Photon, possesses superhuman strength but is extremely simple-minded. He engages in heroic adventures of different varieties. He accidentally gets married to a rebel space pilot named Keyne, and becomes involved in fighting an evil wannabe galactic emperor and his "bumbling henchmen".

The ending song, "Pinch!", is performed by Yui Horie. A manga based on the anime was written by Hiroshi Kanno.

Main characters

• Photon Earth (Voiced by: Junko Takeuchi (Japanese), Scott Cargle (English)): The protagonist, he is extremely strong and fights using a quarterstaff made of black crystal. Has the word "baka" (idiot) scribbled across his forehead by Aun in black ink as he was trying to lead her back home. He's also able to withstand even the strongest blasts of Aho energy, even when its focused directly on him. It was later revealed that he was the source of the un-Aho, which is the reason why Aun's stasis field has no effect on him. Since he was angry at Aun for writing the word idiot in permanent ink, he inscribed the same word on Keyne's forehead, inadvertently marrying her in the process. Though he is simple-minded, he is very trustworthy and loyal to those he promises to protect.
• Aun Freya (Voiced by: Yui Horie (Japanese), Tara Jayne (English)): Photon's spoiled, high-strung, flighty childhood friend, she has the ability to create stasis fields. Humorously, she isn't immune to her own stasis fields and can paradoxically trap herself (and everything around her) in a perpetual stasis field. Photon is the only one who is immune to her stasis field and also is the only one who can get her and keep her out of such messes. In order to cancel out her stasis fields, he has to knock her on the head with his staff. Aun has a tendency of falling in love with every handsome man she encounters, which always ends up in disappointment for her when they turn her down.
• Keyne Aqua (Voiced by: Yumi Kurodaa (Japanese), Suzy Prue (English)): The rebel space pilot who came to Sandy Planet. Photon inadvertently married her when he wrote the word "baka" in katakana on her forehead in black marker. However, she readily accepts the marriage out of fear of being alone and eventually admits her love for Photon.
• Sir Papacharino Nanadan (or Papacha) (Voiced by: Kouichi Yamadera (Japanese), Tristan Goddard (English)): The bumbling antagonist. Also quite perverted when it comes to women. He has an obsession with Keyne and will stop at nothing to have her, but is always foiled by Photon's intervening. He's also quite egotistical and has grand delusions of conquest.
• Princess Lashara Moon (Voiced by: Yuri Amano (Japanese), Carolee Goodgold (English)): Known as the "Flower of the Galaxy" due to her beauty, she's the daughter of the Galactic Emperor. She's madly smitten with Papacha, but what she didn't know is Papacha was really going to user her marriage to increase his harem.
• Bulan (Voiced by: Akiko Hiramatsu (Japanese), Mina Sands (English)): The mysterious servant woman to Lashara, donning a strange looking hat (with feminine lips) and skintight purple attire. Usually moves by hovering on a golden platform and arrives with the princess to Sandy Planet to search out the "Singularity Point". However, she seems to know more about Lashara than she really lets on...
• Pochis (Voiced by: Yuu Asakawa (Japanese), P.M. Lewis (English)): Papacha's cute doll-like henchmen. Excluding Pochi #1 (who acts as a leader figure to the others), there are 28 of them, who refer to each other by their number. Though Papacha believes they're all male, in truth, all the Pochis are really female.

External links

• Photon King Records Site
• Photon: The Idiot Adventures (anime) at Anime News Network's Encyclopedia

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Dansk (Danish)
n. - foton

Nederlands (Dutch)
foton (lichtquant)

Français (French)
n. - photon

Deutsch (German)
n. - Photon

Ελληνική (Greek)
n. - (φυσ.) φωτόνιο

Italiano (Italian)
fotone

Português (Portuguese)
n. - fóton (m)

Русский (Russian)
фотон

Español (Spanish)
n. - fotón

Svenska (Swedish)
n. - foton (fys.)

中文（简体）(Chinese (Simplified))
光子

中文（繁體）(Chinese (Traditional))
n. - 光子

한국어 (Korean)
n. - 광자(빛 에너지)

日本語 (Japanese)
n. - 光子, フォトン

العربيه (Arabic)
‏(الاسم) فوتون : وحدة كم ضوئي‏

עברית (Hebrew)
n. - ‮פוטון (יחידת אנרגיית קרינה, למשל אור)‬

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