Nuclear Physics And Radioactivity Question 262
Question: What percentage of original radioactive atoms is left after five half lives [AFMC 1996; RPMT 1996]
Options:
A) 0.3%
B) 1%
C) 31%
D) 3.125%
Show Answer
Answer:
Correct Answer: D
Solution:
Fraction of atoms remains after five half lives $ \frac{N}{N_{0}}={{( \frac{1}{2} )}^{t/T}}={{( \frac{1}{2} )}^{5T/T}}=\frac{1}{32} $
Þ Percentage atom remains $ =\frac{1}{32}\times 100=3.125% $
BETA
