At any instant, the ratio of the amounts of two radioactive substance is `2:1`. If their half-lives be, respectively, `12h` and `16h`, then after two days, what will be the ratio of the substances?

Options

A. `1 : 1`
B. `2 : 1`
C. `1 : 2`
D. `1 : 4`

Answer

A

Explanation

Number of half-lives in two days for substnces 1 and 2 respectively are `n_(1)=(2xx24)/(12)=4 and n_(2)=(2xx24)/(1.6)=3`
By using `N=N_(0)((1)/(2))^(n)`
`(N_(1))/(N_(2))=((N_(0)))/((N_(0)))xx((1)/(2))^(n1)/((1)/(2))^(n2)`
`(N_(1))/(N_(2))=2/1xx((1)/(2))^(4)/((1)/(2))^(3)1/1`