A radioactive element has a half-life of 8 days. What fraction of the original sample remains after 32 days?

Question

Accepted Answer

$\frac{1}{16}$. The number of half-lives elapsed is 32 ÷ 8 = 4. The fraction remaining after n half-lives is $(\frac{1}{2})^n$, so $(\frac{1}{2})^4 = \frac{1}{16}$. After each successive half-life the sample halves: 1 → 1/2 → 1/4 → 1/8 → 1/16.

Answer

A) $\frac{1}{2}$

Answer

B) $\frac{1}{8}$

Answer

C) $\frac{1}{16}$

Answer

D) $\frac{1}{4}$

A radioactive element has a half-life of 8 days. What fraction of the original sample remains after 32 days?

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