Starting with a sample of pure `.^66 Cu, 7//8` of it decays into `Zn` in `15 min`. The corresponding half-life is.

Answer

5

Explanation

As `7/8` of sample decays, the fraction left is `1/8`
form `N/(N_(0))=(1/2)^(n)=1/8 :. n=3`
As `n=t/T, T=t/n=15/3=5mi n`