JCECE Engineering JCECE Engineering Solved Paper-2004

  • question_answer
    A radioactive element has half-life period\[1600\,\,yr\]. After \[6400\,\,yr\], what part of element will remain?

    A) \[\frac{1}{4}\]                                   

    B) \[\frac{1}{8}\]

    C) \[\frac{1}{16}\]                                

    D) \[\frac{1}{2}\]

    Correct Answer: C

    Solution :

    From Rutherford Soddy law, the number of atoms left after \[n\] half-lives is                 \[N={{N}_{0}}{{\left( \frac{1}{2} \right)}^{n}}\] where,\[n=\frac{time(t)}{half-time({{T}_{1/2}})}\] Given,   \[t=6400\,\,yr,\,\,T=1600\,\,yr\] \[\therefore \]  \[n=\frac{6400}{1600}=4\] So,          \[\frac{N}{{{N}_{0}}}={{\left( \frac{1}{2} \right)}^{n}}={{\left( \frac{1}{2} \right)}^{4}}=\frac{1}{16}\] Hence, \[\frac{1}{16}\] part of element will remain.


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