Atoms And Nuclei Question 365

Question: A 280 days old radioactive substance shows an activity of 6000 dps, 140 days later its activity becomes 3000 dps. What was its initial activity?

Options:

A) 20000 dps

B) 24000 dps

C) 12000 dps

D) 6000 dps

Show Answer

Answer:

Correct Answer: B

Solution:

  • $ \lambda =\frac{2.303}{280}\log \frac{A_{0}}{6000}=\frac{2.303}{420}\log \frac{A_{0}}{3000} $ On solving, we get, $ {{A}_{0}}=24000dps. $


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