The half life of Radon is 3.8 days. Calculate how much of 15 milligram of Radon will remain after 38 days.

Options

A. `0.45mg`
B. `0.30mg`
C. `0.15mg`
D. `0.60mg`

Answer

C

Explanation

Number of half-lives `n = (t)/(T_(1//2)) = (38)/(3.8) = 10`
`(N)/(N_(0)) = ((1)/(2))^(n) = ((1)/(2))^(10)`
`N = (N_(0))/(2^(10))`
mass `prop` number of atoms
`m = (m_(0))/(2^(10)) = (150)/(2^(10)) = 0.15 mg`