Nuclear Chemistry Question 30
Question: A first order nuclear reaction is half completed in 45 minutes. How long does it need 99.9% of the reaction to be completed
[KCET 2001]
Options:
A) 5 hours
B) 7.5 hours
C) 10 hours
D) 20 hours
Show Answer
Answer:
Correct Answer: B
Solution:
$ k=\frac{0.693}{0.75hr}=\frac{2\text{.303}}{t}\log \frac{a}{a-0.999a} $
$ =\frac{2.303}{t}\log 10^{3}=7.5hrs $ .
BETA
