photon

noun

pho·ton | \ ˈfō-ˌtän

Definition of photon

1 : a quantum of electromagnetic radiation Should a substance happen to have a lot of electrons in a higher level, and a lower level is mostly empty …, then a photon can cause an electron to transfer from a higher state to a lower one. This change releases energy and creates a new photon, in addition to the one which caused the transfer. This photon can in turn induce more electrons to fall to a lower state.— Robert Gilmore

2 dated : troland

Other Words from photon Science and the Photon More Example Sentences Learn More about photon

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Science and the Photon

It was Albert Einstein who first theorized that the energy in a light beam exists in small bits or particles, and scientists today know that light sometimes behaves like a wave (somewhat like sound or water) and sometimes like a stream of particles. The energies of photons range from high-energy gamma rays and X-rays down to low-energy infrared and radio waves, though all travel at the same speed. The amazing power of lasers is the result of a concentration of photons that have been made to travel together in order to hit their target at the same time.

Examples of photon in a Sentence

Recent Examples on the Web

The result is that there are a lot of unharvested photons left to rattle around the leaf, damaging the leaf’s essential apparatus. — Paul Cappiello, The Courier-Journal, "Why do some garden leaves turn green, white and yellow? Foliage decoded," 14 June 2019 The sun shines thanks to fusion reactions deep in its core, melding hydrogen atoms into helium and releasing photons in the process. — Stephen Ornes, Discover Magazine, "Our Sun, the Still-mysterious Star That Gives Us Life," 12 June 2019 The color of the photon depends on the perovskite’s chemical constituents, enabling researchers to tune the color by changing the perovskite’s recipe. — Robert F. Service, Science | AAAS, "LEDs created from wonder material could revolutionize lighting and displays," 4 June 2019 All of these systems have specific cells that detect the photon, sound wave, or whatever, and send signals from them to the brain, as does a microphone or video camera connected to a computer. — David Grossman, Popular Mechanics, "Some Humans Can Detect the Earth's Magnetic Field," 19 Mar. 2019 The trick is to not lose the input data: Each photon that is captured by the green sulphur bacteria is utilized. — Peter Byrne, Quanta Magazine, "In Pursuit of Quantum Biology With Birgitta Whaley," 30 July 2013 This time the probe photon’s route would be split into three by partial mirrors. — Philip Ball, Scientific American, "Quantum Physics May Be Even Spookier Than You Think," 21 May 2018 Back at Casa Hofstadter, Penny tells Beverly about Leonard’s new position as co-lead of the photon entanglement team. — Jessica Radloff, Glamour, "The Big Bang Theory," 10 May 2019 The photon is therefore like a particle and so presumably must have gone through one slit or the other. — Andrew Crumey, WSJ, "‘Through Two Doors at Once’ Review: Interfering With Reality," 3 Aug. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'photon.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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9 Jul 2019

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Time Traveler for photon

The first known use of photon was in 1916

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More Definitions for photon

photon

noun

English Language Learners Definition of photon

physics : a tiny particle of light or electromagnetic radiation

See the full definition for photon in the English Language Learners Dictionary

photon

noun

pho·ton | \ ˈfō-ˌtän

Medical Definition of photon

1 : a unit of intensity of light at the retina equal to the illumination received per square millimeter of a pupillary area from a surface having a brightness of one candela per square meter

— called also troland

2 : a quantum of electromagnetic radiation