Nuclear Physics And Radioactivity Question 62
Question: The half life of radium is 1620 years and its atomic weight is 226 kgm per kilomol. The number of atoms that will decay from its 1 gm sample per second will be [MP PMT 1993; BVP 2003]
Options:
A) $ 3.61\times 10^{10} $
B) $ 3.6\times 10^{12} $
C) $ 3.11\times 10^{15} $
D) $ 31.1\times 10^{15} $ (Avogadro’s number $ N=6.02\times 10^{26} $ atom/kilomol)
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Answer:
Correct Answer: A
Solution:
$ \frac{dN}{dt}=\lambda N; $ $ \lambda =\frac{0.6931}{t_{12}}=\frac{0.6931}{1620\times 365\times 24\times 60\times 60}, $ $ N=\frac{6.023\times 10^{23}}{226} $
$ \therefore \frac{dN}{dt}=\frac{0.6931\times 6.023\times 10^{23}}{1620\times 365\times 24\times 60\times 60\times 226} $ $ \frac{1}{2}Mv^{2}=qV. $
BETA
