Nuclear Chemistry Question 7
Question: $ \frac{15}{16}th $ of a radioactive sample decays in 40 days half-life of the sample is
[DCE 2001]
Options:
A) 100 days
B) 10 days
C) 1 day
D) $ {\log _{e}} $ 2 days
Show Answer
Answer:
Correct Answer: B
Solution:
Quantity of radioactive element decayed $ =\frac{15}{16} $ Quantity left = $ 1-\frac{15}{16}=\frac{1}{16} $
$ \frac{1}{16}=1\times {{( \frac{1}{2} )}^{n}} $ or $ {{( \frac{1}{2} )}^{4}}={{( \frac{1}{2} )}^{n}} $ one half-life = $ \frac{40}{4}=10 $ days.
BETA
