Atoms And Nuclei Question 369
Question: After 150 days, the activity of a radioactive sample is 5000 dps. The activity becomes 2500 dps after another 75 days. The initial activity of the sample is
Options:
A) 20000 dps
B) 40000 dps
C) 7500 dps
D) 10000 dps
Show Answer
Answer:
Correct Answer: A
Solution:
- Activity of sample becomes 2500 from 5000 in 75 days therefore its half-life is 75 days, so $ R=\frac{R_{0}}{{{2}^{\frac{150}{75}}}}=5000\Rightarrow R_{0}=5000\times 4=20,000 $
