# Math

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A radio substance has a half-life of 10 years. What is its annual decay rate?

• Math -

The annual decay rate is what you multiply the number of radioactive atoms by to get the decay rate, k, in atoms per year.

See http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/halfli2.html

The decay rate is 0.693 divided by the half life, or 0.0693 yr^-1 in this case.

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