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mean life

   Also found in: Dictionary/thesaurus, Acronyms, Wikipedia, Hutchinson 0.02 sec.

mean life

In radioactivity, the average lifetime of all the nuclei of a particular unstable atomic species. This time interval is the sum of the lifetimes of all the individual unstable nuclei in a sample, divided by the total number of unstable nuclei present. It is the reciprocal of the decay constant. For a given isotope, the mean life is always 1.443 times its half-life. For example, lead-209 decays to bismuth-209 with a half-life of 3.25 hours and a mean life of 4.69 hours.


mean life [′mēn ′līf]
(physics)
The average time during which a system, such as an atom, nucleus, or elementary particle, exists in a specified form; for a radionuclide or an excited state of an atom or nucleus, it is the reciprocal of the decay constant. Also known as average life; lifetime.


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It will mean life more abundant for the manhood of the young boys born and growing up--ay, and life more abundant for the young girls born and growing up to share the lives of the young men.
I perceive that we inhabitants of New England live this mean life that we do because our vision does not penetrate the surface of things.
 
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