Carbon-11 is a radioactive isotope of carbon. Its half-life is 20.3 minutes. What fraction of the initial number of carbon-11 atoms in a sample will remain after 81 minutes

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Quizplus · Accepted Answer

The half-life of carbon-11 is 20.3 minutes. This means that after 20.3 minutes, half of the carbon-11 atoms in a sample will have decayed. After another 20.3 minutes, half of the remaining carbon-11 atoms will have decayed, and so on. After 81 minutes, which is four half-lives, only 1/16 of the original number of carbon-11 atoms will remain.

Carbon-11 Is a Radioactive Isotope of Carbon