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The half lives of two longest-lived radi...

The half lives of two longest-lived radioactive isotopes of phosphorus `P^(32)` and `P^(33)`, are 14 days and 28 days respectively. A sample has been prepared by mxing the two isotopes in the ratio of 4:1 of their atoms. Initial activity of the mixed sample is 9.0mCi. Find the activity of the sample after 80 days.
Take `ln2=0.7` and `e^(-2)=0.14`

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The correct Answer is:
0.3mCi
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