The decay constant () of Cobalt-60 is given as . What is the approximate decay activity (in disinteg — Nuclear Chemistry and Radioactivity Chemistry Question
Question
The decay constant ($\lambda$) of Cobalt-60 is given as $2.5 \times 10^{-7}\text{ min}^{-1}$. What is the approximate decay activity (in disintegrations per minute) of a $2.0\text{ g}$ sample of Cobalt-60?
Answer: A
💡 Solution & Explanation
Moles of Co-60 = $2/60 = 1/30$. Number of atoms $N = (1/30) \times 6.023 \times 10^{23} \approx 2.0 \times 10^{22}$. Activity $A = \lambda N = (2.5 \times 10^{-7}) \times (2.0 \times 10^{22}) = 5.0 \times 10^{15}\text{ dpm}$.
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