The half-life of radon is 3.8 days. How many radon will be left out of 1024 mg after 38 days :

Options

A. 1 mg
B. 2 mg
C. 3 mg
D. 4 mg

Answer

A

Explanation

From Rutherford-Soddy law
`" "N=N_(0)(1/2)^(n)`
`" "n=(38)/(3.8)=10`
The initial quantity of radon is `N_(0)=1024mg`.
Therefore, the mass of radon left after 10 half-lives is
`" "N=1024 times (1/2)^(10)=(1024)/(1024)=1mg`