NEET Sample Paper NEET Sample Test Paper-33

  • question_answer
    When the half life of any sample of radioactive substance is 4 days, then the fraction of sample will remain undecayed after 2 days, will be:

    A)  \[\sqrt{2}\]              

    B)  \[\frac{1}{\sqrt{2}}\]

    C)  \[\frac{\sqrt{2}-1}{\sqrt{2}}\]

    D)  \[\frac{1}{2}\]

    Correct Answer: B

    Solution :

    According to Rutherford-Soddy law the fraction left after n half-lives is given by \[N={{N}_{0}}{{\left( \frac{1}{2} \right)}^{n}}\] Where n is the number of half-lives. \[n=\frac{time(t)}{half-life}=\frac{2}{4}=\frac{1}{2}\] So, \[\frac{N}{{{N}_{0}}}={{\left( \frac{1}{2} \right)}^{1/2}},\]   \[\frac{N}{{{N}_{0}}}=\frac{1}{\sqrt{2}}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner