Atoms And Nuclei Question 392
Question: Starting with a sample $ ^{66}Cu,\frac{7}{8} $ of pure decays into Zn in 15 minutes. The corresponding half-life is
Options:
A) 15 minutes
B) 10 minutes
C) $ 7\frac{1}{2} $ minutes
D) 5 minutes
Show Answer
Answer:
Correct Answer: D
Solution:
- $ \frac{7}{8} $ of $ Cu $ decays in 15 minutes.
$ \therefore $ $ Cu $ undecayed $ =N=1-\frac{7}{8}=\frac{1}{8}={{( \frac{1}{2} )}^{3}} $
$ \therefore $ No. of half lifes = 3 $ n=\frac{t}{T} $ or $ 3=\frac{15}{T} $
$ \Rightarrow $ T = half-life period $ =\frac{15}{3}=5 $ minutes
