A radioactive isotope has a half-life of hours. What fraction of the original nuclei remains after hours?
Answer and explanation
Correct answer: C.
- Step 1: Number of half-lives .
- Step 2: Fraction remaining .
Answer
.
Why not the others: : rounds the number of half-lives up to . : rounds the number of half-lives down to . : subtracts the half-life from the time.
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