Nuclear Physics And Radioactivity Question 86
Question: If one starts with one curie of radioactive substance (T1/2 = 12 hrs) the activity left after a period of 1 week will be about
Options:
A) 1 curie
B) 120 micro curie
C) 60 micro curie
D) 8 mili curie
Show Answer
Answer:
Correct Answer: C
Solution:
1 week » 7 days $ \underline{\tilde{\ }} $ $ 7\times 24hrs\underline{\tilde{\ }},\ 14 $ half lives Number of atoms left $ =\frac{No}{{{(2)}^{14}}} $ , Activity = $ N\lambda $ \ Activity left is $ \frac{1}{{{(2)}^{14}}} $ times the initial
Þ $ \frac{1}{{{(2)}^{14}}}\times 1 $ curie $ =\frac{1}{16384}\times 1 $ curie $ \cong $ $ 61\times {{10}^{-6}} $ curie $ \approx 60\mu , $ curie.
BETA
