A Sample Of Radioactive Substance Has 106 radioactive Nuclei. Its Half-life Time Is 20 Seconds. How Many Nuclei Will Remain After 10 Seconds?

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Question

A sample of radioactive substance has 10⁶ radioactive nuclei. Its half-life time is 20 seconds. How many nuclei will remain after 10 seconds?

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Solution

Correct option is

If in a sample of radioactive substance the initial number of nuclei be N₀, then the number of nuclei after n half-lives is given by

The half-life of the radioactive substance is 20 seconds. The number of half-lives in 10 seconds is

.

The initial number of nuclei is . Hence the number of nuclei left after half-life will be

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