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Question
If the number of nuclei in a radioactive sample at a given time is N, what will be the number at the end of two half-lives?
Options
`N/2`
`N/4`
`(3N)/4`
`N/8`
Solution
`N/4`
Explanation:
The number of nuclei in a radioactive sample at a given time is N.
After the first half-life the remaining nuclei are, `N/2`
After the second half-life the remaining nuclei are, `(N/2)/2 = N/4`
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