Calculate the half life periode of a radioactive substance if its activity drops to `1/16` th of its initial value of 30 yr.

Answer

`7.5 yr`

Explanation

`T=?, N/(N_(0))=1/16, t=30years`
As `N/(N_(0))=(1/2)^(n)=1/16=(1/2)^(4)`
`:. n=4=t/T,T=t/4=30/4=7.5 years`