Nuclear Physics And Radioactivity Question 285
Question: A radioactive element emits 200 particles per second. After three hours 25 particles per second are emitted. The half-life period of element will be
Options:
A) 50 minutes
B) 60 minutes
C) 70 minutes
D) 80 minutes
Show Answer
Answer:
Correct Answer: B
Solution:
$ R=\frac{dN}{dt}\propto N\Rightarrow \frac{R_{2}}{R_{1}}=\frac{N_{2}}{N_{1}} $ But $ \frac{N_{2}}{N_{1}}={{( \frac{1}{2} )}^{{t_{1/2}}}}\Rightarrow \frac{25}{200}=\frac{1}{8}={{( \frac{1}{2} )}^{3}}\Rightarrow \frac{t}{{t_{1/2}}}=3 $
$ \therefore {t_{1/2}}=\frac{t}{3}=\frac{3}{3}=1\ hour=60 $ minutes
BETA
