Half-life is the interval over which an exponentially decaying population’s expected size is halved.
Difficulty
Intermediate
Read time
5 min
Prerequisites
Basic algebra, consistent units, and the stated model assumptions
Source
OpenStax, College Physics 2e, §31.4 (Paul Peter Urone and Roger Hinrichs)OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example.
Half-life is the interval over which an exponentially decaying population’s expected size is halved. It is inversely proportional to the decay constant.
| Symbol | Meaning | Units |
|---|---|---|
| Time (half life) | ||
| Decay Constant |
Convert a decay constant into half-life.
Compare exponential decay rates.
Find the half-life for a decay constant of 0.100 s⁻¹.
OpenFormulaGraph equation reference; FormuLab adaptation details and license are provided below.
Adapted from OpenFormulaGraph, under CC BY 4.0.
FormuLab adapted wording, notation, applicability conditions and topic placement, and expanded the numerical check into a worked example.
Assumptions
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