Nuclear Physics And Radioactivity Question 338
Question: A radioactive substance has a half-life of 1 year. The fraction of this material, that would remain after 5 years will be [CPMT 2000]
Options:
A) $ \frac{1}{32} $
B) $ \frac{1}{5} $
C) $ \frac{1}{2} $
D) $ \frac{4}{5} $
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Answer:
Correct Answer: A
Solution:
Number of half lives $ n=\frac{5}{1}=5 $ Now $ \frac{N}{N_{0}}={{( \frac{1}{2} )}^{n}}\Rightarrow \frac{N}{N_{0}}={{( \frac{1}{2} )}^{5}}=\frac{1}{32} $
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