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3 years ago

14

The half-life of radioactive actinium (^227 Ac) is 22 years. How much will remain after 15 years? Find R first.

1 answer:

Llana [10]3 years ago

5 0

Use the formula below.

Let A_0 = 1 because you just want to know the percentage left. Usually that's the initial amount.

t = 15, the number of years past. n = 22, the half-life.

$A=A_0(0.5)^{\frac{t}{n}} \\ \\ A=0.5^{\frac{15}{22}} \\ \\ A=0.62 = 62\%$

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