Nuclear Physics And Radioactivity Question 306
Question: Radon (Ra) decays into Polonium ( $ P_{0} $ ) by emitting an $ \alpha - $ particle with half-life of 4 days. A sample contains $ 6.4\times 10^{10} $ atoms of $ Rn $ . After 12 days, the number of atoms of $ R_{n} $ left in the sample will be [MP PET 1999, Pb. PMT 2004]
Options:
A) $ 3.2\times 10^{10} $
B) $ 0.53\times 10^{10} $
C) $ 2.1\times 10^{10} $
D) $ 0.8\times 10^{10} $
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Answer:
Correct Answer: D
Solution:
In the given case, 12 days = 3 half lives Number of atoms left after 3 half lives. $ =6.4\times 10^{10}\times \frac{1}{2^{3}}=0.8\times 10^{10} $
BETA
