Nuclear Physics And Radioactivity Question 332
Question: The activity of a sample is 64 × 10?5 Ci. Its half-life is 3 days. The activity will become 5 × 10?6 Ci after [MP PET 2003]
Options:
A) 12 days
B) 7 days
C) 18 days
D) 21 days
Show Answer
Answer:
Correct Answer: D
Solution:
$ A=A_{0}{{( \frac{1}{2} )}^{t/{T_{1/2}}}}\Rightarrow 5\times {{10}^{-6}}=64\times {{10}^{-5}}{{( \frac{1}{2} )}^{t/3}} $
$ \Rightarrow \frac{1}{128}={{( \frac{1}{2} )}^{t/3}}\Rightarrow t=21 $ days
BETA
