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10-25

mean duration of life, mean life time

URNurn:iso:std:iso:80000:-10:ed-2:en:item:10-25

https://metanorma.github.io/isq-smart/quantities/part-10/t10-25
urn:iso:std:iso:80000:-10:ed-2:en:item:10-25

ISQ Identifiers

ISO

urn:iso:std:iso:80000:-10:ed-2:en:item:10-25

IEC

urn:iec:std:iec:80000-10:2019:::item:10-25

Designations

ENmean duration of life

FRdurée de vie moyenne

ENmean life time

FRvie moyenne

Symbol

τ

Notation systems

Rendered

τ

AsciiMath

tau

LaTeX

\tau

Definition

reciprocal of the decay constant $λ$ (decay constant):

τ = \frac{1}{λ}

inverse de la constante de désintégration $λ$ (decay constant):

τ = \frac{1}{λ}

Units

s

second

View related quantities →

Notes

Mean duration of life is the expected value of the duration of life of an unstable particle or an excited state of a particle when the number of decay events in a short time interval follows a Poisson distribution.

La durée de vie moyenne est l'espérance mathématique de la durée de vie d'une particule instable ou d'un état excité d'une particule lorsque le nombre d'événements de désintégration dans un court intervalle de temps suit la loi de Poisson.

Referenced by

level width

Concept HierarchyPendrill (2024)

Ttime-type quantitiesLevel 0 · Kind

Broader concepts

◇ time-type quantities

Ontology
isq:Quantity smart:TermEntry

Class Hierarchy

smart:Entity smart:TermEntryisq:Quantity

A physical quantity as defined in ISO/IEC 80000, with associated symbols, definitions, and units of measurement.

Instance IRI

isq:t10-25

Properties

isq:QuantityShape

Property	Value
rdf:type	isq:Quantity smart:TermEntry
dcterms:identifier	10-25
skosxl:prefLabel	"mean duration of life"@en
skosxl:altLabel	"mean life time <atomic and nuclear physics>"@en"tau"@en
skos:definition	reciprocal of the decay constant stem:[lambda] (<<t10-24>>): [stem%unnumbered] ++++ tau = 1/lambda ++++
skos:note	Mean duration of life is the expected value of the duration of life of an unstable particle or an excited state of a par…
isq:hasUnit	s (second)
isq:hasDimension	isq:Dimension
smart:hasBindingnessType	bindingness-type:normative
dcterms:isPartOf	isq:part-10

Related Entities

isq:QuantityShape isq:part-10 isq:Unit isq:Dimension isq:hasDimension smart:TermEntry