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alpha particle
noun
: a positively charged nuclear particle identical with the nucleus of a helium atom that consists of two protons and two neutrons and is ejected at high speed in certain radioactive transformations
called also alpha, alpha radiation, alpha ray
Examples of alpha particle in a Sentence
Recent Examples on the Web
Compared to beta particles, alpha particles are larger and more energetic.
—Discover Magazine, 8 July 2024
Another key advantage of alpha particles is their limited travel distance.
—Discover Magazine, 8 July 2024
The most common forms occur when an unstable nucleus spits out an alpha particle, consisting of two neutrons and two protons, a beta particle consisting of an energetic positron or electron, or a gamma ray, consisting of a high energy photon.
—The Physics Arxiv Blog, Discover Magazine, 27 Feb. 2024
An alpha particle is made of two protons and two neutrons.
—WIRED, 8 Sep. 2023
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Word History
First Known Use
1903, in the meaning defined above
Dictionary Entries Near alpha particle
Cite this Entry
“Alpha particle.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/alpha%20particle. Accessed 13 Dec. 2024.
Kids Definition
alpha particle
noun
: a positively charged particle that is identical with the nucleus of a helium atom, consists of 2 protons and 2 neutrons, and is thrown at high speed from a radioactive atomic nucleus
Medical Definition
alpha particle
noun
: a positively charged nuclear particle identical with the nucleus of a helium atom that consists of two protons and two neutrons and is ejected at high speed in certain radioactive transformations
called also alpha, alpha ray
More from Merriam-Webster on alpha particle
Britannica.com: Encyclopedia article about alpha particle
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