Nuclear Physics And Radioactivity Question 376
Question: A sample of radioactive element has a mass of 10 gm at an instant t = 0.The approximate mass of this element in the sample after two mean lives is [CBSE PMT 2003]
Options:
A) 2.50 gm
B) 3.70 gm
C) 6.30 gm
D) 1.35 gm
Show Answer
Answer:
Correct Answer: D
Solution:
$ M=M_{0}{{e}^{-\lambda t}}; $ given $ t=2( \frac{1}{\lambda } ) $
$ \Rightarrow M=10{{e}^{-\lambda ( \frac{2}{\lambda } )}}=10{{( \frac{1}{e} )}^{2}}\Rightarrow M=1.35\ gm $
BETA
