Q 12-13-072JEE MainJEE Main 2023 (15 Apr, Shift 1)Easy
The half-life of a radioactive nucleus is $5$ years. The fraction of the original sample that would decay in $15$ years is
Answer: (C) $\dfrac78$
$15$ years $=3$ half-lives, so $\dfrac18$ remains and $\dfrac78$ has decayed.
Solution by Sreeraj P, M.Sc Physics