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The activity of a radioactive isotope f...

The activity of a radioactive isotope falls to 12.5% in 90 days. Calculate the half life and decay constant.

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`N_(0)=100 N=12.5 t=90 days`
decay constant `lambda=(2.303)/(t) log (N_(0))/(N)`
`=0.02558 log 8`
`=2.311xx10^(-2) days^(-1)`
`t^(1//2)=(0.693)/(lambda)=(0.963)/(2.311xx10^(-2))=29.99 days`
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NCERT BANGLISH-NUCLEAR CHEMISTRY-SELF EVALUATION
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  12. Define radio activity.

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  13. What is half life period.

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