Modern Physics 7 Question 44
49. To determine the half-life of a radioactive element, a student plots a graph of versus . Here is the rate of radioactive decay at time . If the number of radioactive nuclei of this element decreases by a factor of after , the value of is
(2010)
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Answer:
Correct Answer: 49.
Solution:
Activity of radioactive substance
Taking
Hence,
From the graph we can see that,
Now applying the equation,
i.e, nuclei decreases by a factor of 8 .
Hence, the answer is 8.