The half-life of a quantity undergoing exponential decay is the time required for the quantity to decrease to one-half of its initial
value. If
with decay constant 
, then the half-life is
The half-life is therefore 
times the characteristic decay time 
.
See also
Decay Constant,
Exponential
Decay
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References
Boyce, W. E. and DiPrima, R. C. Elementary Differential Equations and Boundary Value Problems, 9th ed. Hoboken, NJ:
Wiley, 2009.
Cite this as:
Weisstein, Eric W. "Half-Life." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Half-Life.html
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