Chemical Kinetics - Result Question 67
####66. One of the hazards of nuclear explosion is the generation of $Sr^{90}$ and its subsequent incorporation in bones. This nucleide has a half-life of $28.1 yr$. Suppose one microgram was absorbed by a new-born child, how much $Sr^{90}$ will remain in his bones after $20 yr$.
(1995, 2M)
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Answer:
Correct Answer: 66. $(0.25)$
Solution:
$$ k _t=\ln \frac{w _0}{w} $$
$\Rightarrow \quad \frac{\ln 2}{28.1} \times 20=\ln \frac{10^{-6} g}{w} \Rightarrow w=6.1 \times 10^{-7} g$
