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NEET Sample Paper NEET Sample Test Paper-59

  • question_answer
    The masses of two radioactive substance are same and their half-lives are 1 hr and 2yr respectively. The ratio of their activities after 4yr will be:

    A) 1 : 4                             

    B) 1 : 2  

    C) 1 : 3                             

    D) 1 : 6

    Correct Answer: A

    Solution :

    [a] T=4 year \[{{t}_{{}^{1}/{}_{2}}}=1\,year\,{{t}_{{}^{1}/{}_{2}}}=2year\] \[n=\frac{T}{{{t}_{{}^{1}/{}_{2}}}}=4n=\frac{4}{2}=2\] \[{{N}_{1}}={{N}_{o}}{{\left[ \frac{1}{2} \right]}^{4}}{{N}_{2}}={{N}_{o}}{{\left[ \frac{1}{2} \right]}^{2}}\] \[\frac{{{N}_{1}}}{{{N}_{2}}}=\frac{1}{4}\]


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