The activity of a sample reduces from A0 to $\frac{A_0}{\sqrt 3}$ in one hour. The activity after 3 hours more will be
Answer & explanation
Correct answer: option 1
$A_1 = A_0 e^{-\lambda t}$
$\Rightarrow \frac{A_0}{\sqrt 3} = A_0 e^{-\lambda}$ .....(1)
$ A' = A_0 e^{-3\lambda} = A_0 (\frac{1}{\sqrt 3})^3 = A_0 \frac{1}{3\sqrt 3}$