# What fraction of the original number of atoms of a radioactive substance will remain unresolved after 4 days

August 22, 2020 | Education

| **What fraction of the original number of atoms of a radioactive substance will remain unresolved after 4 days if the half-life of this element is known to be 2 days?**

Half-life is the time it takes for half of the available atoms to decay. This means that after the first two days of the atoms there are half (1/2) left. And two days later, the number of remaining atoms was again reduced by half. And half of half is 1/4.

Answer: 1/4.

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