Nuclear Physics And Radioactivity Question 272
Question: The half-life of $ Bi^{210} $ is 5 days. What time is taken by (7/8)th part of the sample to decay [MNR 1986; Pb. PMT 2001]
Options:
A) 3.4 days
B) 10 days
C) 15 days
D) 20 days
Show Answer
Answer:
Correct Answer: C
Solution:
By using $ N=N_{0}{{( \frac{1}{2} )}^{t/T}}; $ where $ N=( 1-\frac{7}{8} ),N_{0}=\frac{1}{8}N_{0} $ So $ \frac{1}{8}N_{0}=N_{0}{{( \frac{1}{2} )}^{t/T}} $
Þ $ {{( \frac{1}{2} )}^{3}}={{( \frac{1}{2} )}^{t/5}} $
Þ t =15 days.
BETA
