Nuclear Physics And Radioactivity Question 305
Question: The half-life period of a radioactive substance is 5 min. The amount of substance decayed in 20 min will be [MP PMT/PET 1998]
Options:
A) 93.75%
B) 75%
C) 25%
D) 6.25%
Show Answer
Answer:
Correct Answer: A
Solution:
Number of half lives in 20 min = n $ =\frac{20}{5}=4 $ Fraction of material remains after four half lives $ =\frac{1}{16} $ Hence fraction that decays $ =1-\frac{1}{16}=\frac{15}{16}=93.75% $
BETA
