Engineering Board Exam Reviewer · Chemistry · hard
The activity of a radioactive sample drops from 800 counts/min to 100 counts/min in 30 minutes. What is its half-life?
- 3.75 min
- 15 min
- 10 min
- 30 min
Answer
C. 10 min
Solution
800 → 400 → 200 → 100 is three half-lives in 30 min t1/2 = 10 min.
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