Typical radio active decay question(adsbygoogle = window.adsbygoogle || []).push({});

Half time = 1 year

λ = ln 2 here

Q 1: if we have 1024 atoms at t=0, what is the time at which the expected number remaining is one.

Easy, I get 10 years

Q 2: The chance that in fact none of the 1024 atoms remains after the time calculated in c:

it should be P(T<10 years) = 1 - P(T>10 years) but I get different answers.

The answer given is e^{-1}

any hints please? I know it's easy, I'm just missing something

Thanks

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# Exponential Distribution and radio active decay

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