Q 12-13-080JEE MainJEE Main 2023 (8 Apr, Shift 2)Easy
A radioactive material is reduced to $\dfrac18$ of its original amount in $3$ days. If $8\times10^{-3}$ kg of the material is left after $5$ days the initial amount of the material is
Answer: (D) $256\ \text{g}$
$\dfrac18$ in $3$ days means a half-life of $1$ day. After $5$ days $\dfrac1{32}$ remains: $N_0=32\times8\ \text{g}=256$ g.
Solution by Sreeraj P, M.Sc Physics