Q 12-13-018NEETJEE MainMedium
The activity of a radioactive sample falls to $\dfrac{1}{8}$ of its initial value in $24$ hours. Its half-life is
Answer: (A) $8$ h
$\dfrac{1}{8} = \left(\dfrac{1}{2}\right)^3$: three half-lives in $24$ h, so $T_{1/2} = 8$ h.
Solution by Sreeraj P, M.Sc Physics