Nuclear Physics And Radioactivity Question 340
Question: If half-life of a substance is 3.8 days and its quantity is 10.38 gm. Then substance quantity remaining left after 19 days will be [RPMT 2000; AFMC 2002]
Options:
A) 0.151 gm
B) 0.32 gm
C) 1.51 gm
D) 0.16 gm
Show Answer
Answer:
Correct Answer: B
Solution:
Number of half lives $ n=\frac{19}{3.8}=5; $ Now $ \frac{N}{N_{0}}={{( \frac{1}{2} )}^{n}} $
$ \Rightarrow \frac{N}{10.38}={{( \frac{1}{2} )}^{5}}\Rightarrow N=10.38\times {{( \frac{1}{2} )}^{5}} $ $ =0.32gm $
BETA
