A radio-isotope has a half-life of `5` yeard. The fraction of the atoms of this material that would decay in `15` years will be

Options

A. `1//8`
B. `2//3`
C. `7//8`
D. `5//8`

Answer

C

Explanation

Number of nuclei remaining `= (N_(0))/(2^(n)) = (N_(0))/(2^(3)) = (N_(0))/(8) [n = (15)/(5)= 3]`
Decayed fraction `= 1 - (1)/(8)= (7)/(8)`