2. Sample Papers
  3. NEET

NEET Sample Paper NEET Sample Test Paper-28

  • question_answer
    The counting rate observed from a radioactive source at \[t=0\] second was 1600 counts per second and at \[t=8\] seconds it was 100 counts per second. The counting rate observed, as counts per second at \[t=4\] second will be :-

    A)  400           

    B)  300

    C)  200               

    D)  150

    Correct Answer: A

    Solution :

    \[R=\frac{{{R}_{0}}}{{{2}^{{\scriptstyle{}^{t}/{}_{Th}}}}}\] \[100=\frac{1600}{{{2}^{{\scriptstyle{}^{t}/{}_{Th}}}}}\] \[{{2}^{t/Th}}={{2}^{4}}\] or \[{{T}_{h}}=\frac{t}{4}=\frac{8}{4}=2\sec \] \[R'=\frac{{{R}_{0}}}{{{2}^{{\scriptstyle{}^{t'}/{}_{Th}}}}}=\frac{1600}{{{2}^{{\scriptstyle{}^{4}/{}_{2}}}}}=400\]               


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