Question 144265
A certain radioactive isotope decays at a rate of 0.1% annually. Determine the half-life of this isotope, to the nearest year.
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A(t) = Ao(1-0.001)^t
(1/2)Ao = Ao(0.999)^t
0.999^t = (1/2)
t = [log(1/2) / log(0.999)]

t = 692.80 years
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Cheers,
Stan H.