One gm of an element decays by `beta`-emission to 0.125 gm in 200 years . The half life period of the reaction is

Options

A. 0.014 years
B. 6.66 years
C. 66.6 years
D. 666 years

Answer

C

Explanation

`N_(0)=1 g , N=0.125`
`therefore 2^(n)=(N)/(N_(0))=(1)/(0.125)=(1000)/(125)=8=2^(3)`
`therefore n=3`
`3xxt_(1//2)=200` years
`t_(1//2)=(200)/(2)` years=66.67 years