Nuclear Chemistry Question 11
Question: Percentage of a radioactive element decayed after 20 sec when half-life is 4 sec
[BHU 2003]
Options:
A) 92.25
B) 96.87
C) 50
D) 75
Show Answer
Answer:
Correct Answer: B
Solution:
$ n=\frac{20}{4}=5,\frac{N _{t}}{N _{o}}={{( \frac{1}{2} )}^{5}}=\frac{1}{32},\therefore decayed $
$ =( \text{1–}\frac{1}{32} )\times 100=\frac{31}{32}\times 100=96.87 $ .
BETA
