Nuclear Physics And Radioactivity Question 282
Question: The half-life of polonium is 140 days. After how many days, 16 gm polonium will be reduced to 1 gm (or 15g will decay) [CPMT 1997; Pb. PET 2002; BHU 2004]
Options:
A) 700 days
B) 280 days
C) 560 days
D) 420 days
Show Answer
Answer:
Correct Answer: C
Solution:
$ \frac{N}{N_{0}}={{( \frac{1}{2} )}^{t/140}}\Rightarrow \frac{1}{16}={{( \frac{1}{2} )}^{t/140}}. $
$ \Rightarrow \frac{t}{140}=4\Rightarrow t=560\ days $
BETA
