If `N_(0)` is the original mass of the substance of half - life period `t_(1//2) = 5 year` then the amount of substance left after `15` year is

Options

A. `N_(0)//8`
B. `N_(0)//16`
C. `N_(0)//2`
D. `N_(0)//4`

Answer

A

Explanation

After every half - life , the mass of the substance reduces to half its initial value
`N_(0) overset(5year)rarr N_(0)/(2) overset(5 years)rarrN_(0)/(2^(2)) overset(5 years)rarrN_(0)/(8)`