Atoms And Nuclei Question 377

Question: The activity of a radioactive sample is A1 at time t1 and A2 at time t2 . If τ is average life of sample then the number of nuclei decayed in time ( t2t1 ) is

Options:

A) A1t1A2t2

B) (A2A1)2τ

C) (A1A2)(t2t1)

D) (A1A2)τ.

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Answer:

Correct Answer: D

Solution:

  • Let N0 be the initial number of nuclei, then

    N1=N0eλt1

    and N2=N0eλt2

    Number of nuclei decayed =N1N2 =N0(eλt1eλt2)=A0λ(eλt1eλt2)

    =A1A2λ=(.A1A2)τ.



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