2. Solved Papers
  3. Punjab Medical

Punjab Medical Punjab - MET Solved Paper-1999

  • question_answer
    A piece of wood was found to have \[{{C}^{14}}/{{C}^{12}}\] ratio \[0.7\] times that in a living plant. The time period when the plant died is (half-life of\[{{C}^{14}}=5760\,\,yr\])

    A) \[2980\,\,yr\]                    

    B) \[3070\,\,yr\]

    C) \[2966\,\,yr\]                    

    D) \[2770\,\,yr\]

    Correct Answer: C

    Solution :

    Here: Initial activity of wood \[({{N}_{0}})=1;\]final activity of wood\[({{N}_{1}})=0.70\]and half-life\[{{t}_{1/2}}=5760\,\,yr\]. We know that disintegration constant                 \[(\lambda )=\frac{0.693}{{{t}_{1/2}}}=\frac{0.693}{5760}\] We also know that                 \[(t)=\frac{2.303}{k}\log \frac{{{N}_{o}}}{{{N}_{t}}}t=\frac{2.303}{k}.\log \frac{1}{7}\] or\[\frac{2.303\times 5760\times 0.155}{0.693}=2966\,\,yr\].


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