The half-life of radon is `3.8` days. Three forth of a radon sample decay in.

Options

A. `5.02` days
B. `15.2` days
C. `7.6` days
D. `11.4` days

Answer

C

Explanation

( c) Decayed fraction `= (3)/(4)`, so undecayed fraction `= (1)/(4)`
Now `(N)/(N_0) = ((1)/(2))^n rArr (1)/(4) = ((1)/(2))^n rArr n = 2`
`rArr t = n xx T_(1//2) = 2 xx 3.8 = 7.6 days`.