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NEET Sample Paper NEET Sample Test Paper-10

  • question_answer
    The activity of a radioactive nuclide is \[2\times {{10}^{7}}\] disintegrations per minute. After \[23.03\text{ }min,\]its activity is reduced to\[2\times {{10}^{6}}dpm\]. What is the average life of the nuclide?

    A)  100 min                     

    B)  10 min

    C)  50 min                       

    D)  5 min

    Correct Answer: B

    Solution :

    \[k=\frac{2.303}{t}\,\log \,\frac{{{N}_{0}}}{N}\] \[=\frac{2.303}{23.03}\log \frac{2\times {{10}^{7}}}{2\times {{10}^{6}}}\] \[=\frac{2.303}{23.03}\log 10\] \[k=0.1\,{{\min }^{-1}}\] \[{{t}_{{\scriptstyle{}^{1}/{}_{2}}}}=\frac{0.693}{k}=\frac{0.693}{0.1}=6.93\,\,min\] average life \[(T)=1.44\times {{t}_{{\scriptstyle{}^{1}/{}_{2}}}}\]                 \[=1.44\times 6.93=10\,\,\min \]


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