After 3 half-lives, the remaining fraction of a radioactive sample is:
- A. 1/2
- B. 1/4
- C. 1/8
- D. 1/16
Explanation
Each half life halves the number of undecayed nuclei, so three of them give a half multiplied by a half multiplied by a half, which is one eighth. Decay is exponential, so the fractions multiply rather than the half lives adding in any simple way. After four half lives one sixteenth would remain.
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