If the half life period of a substance is 5 years, then the total amount of the substance left after 15…
If the half life period of a substance is 5 years, then the total amount of the substance left after 15 years, when initial amount is $64 \mathrm{gms}$ is
8 gms
16 gms
2 gms
32 gms
Solution
Half life period $=5$ years
Initial quantity of substance $=64$ grams
$\therefore$ Quantity left after 5 years $=\frac{64}{2}=32$ grams
$\therefore$ Quantity left after 10 years $=\frac{32}{2}=16$ grams
$\therefore$ Quantity left after 15 years $=\frac{16}{2}=8$ grams