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BCECE Engineering BCECE Engineering Solved Paper-2014

  • question_answer
    Two radioactive sources X and Y of half lives 1h and 2 h respectively initially contain the same number of radioactive atoms. At the  end of 2 h, their rates of disintegration are in the ratio of

    A) 4: 3                        

    B) 3:4    

    C) 1 :2                        

    D) 2 :1

    Correct Answer: C

    Solution :

    Rate of disintegration \[\alpha \] number of atoms left For \[X\]              \[\frac{N}{{{N}_{0}}}={{\left( \frac{1}{2} \right)}^{2}}=\frac{1}{4}\] For \[Y\]               \[\frac{N}{{{N}_{0}}}={{\left( \frac{1}{2} \right)}^{1}}=\frac{1}{2}\] \[\therefore \]  \[\frac{{{R}_{X}}}{{{R}_{\gamma }}}=\frac{\frac{{{N}_{0}}}{4}}{\frac{{{N}_{0}}}{2}}=\frac{1}{2}\]


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