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Radioactive decay

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Radioactivity index
Radioactive decay diagram
calc
This calc gives the remaining activity (as a fraction of the original activity) of a sample with known half-life after a given time. A simple exponential decay model is used.
Half-life
Time

Fraction remaining
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notes
Isotope half-lifes range from immeasurably short times for very unstable isotopes to incredibly long ones (millions of years even).
This calc can also be used to calculate the amount of decay for any other exponential (first-order) process with a known half-life.