The half life of radioactive Radon is `3.8 days` . The time at the end of which `(1)/(20) th` of the radon sample will remain undecayed is `(given log e = 0.4343 ) `

Options

A. (a) 3.8 days
B. (b) 16.5 days
C. (c) 33 days
D. (d) 76 days

Answer

B

Explanation

Using `N=N_0e^(-lambdat)`
where, `lambda=(1n2)/(t_(1//2))=(1n2)/(3.8)`
`:.` `N_0/20=N_0e^(-(1n2)/(3.8)t)`
Solving this equation with the help of given data we find
`t=16.5 days`
`:.` Correct option is (b).