The half life period of radio active isotope is 5 minutes. The fraction of isotope, that will be remaining after 30 minutes is

Options

A. `1//16`
B. `1//36`
C. `1//64`
D. `1//32`

Answer

C

Explanation

Here `n=t/T=30/5 =6`
Now `N/N_(0) =(1/2)^(n)`
`=(1/2)^(6)`
`=1/64`