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12th Class Chemistry Nuclear Chemistry / नाभिकीय रसायन Question Bank Critical Thinking Nuclear chemistry

  • question_answer
    A wood specimen from an archeological centre shows a \[_{6}^{14}C\] activity of 5.0 counts/min/gm of carbon. What is the age of the specimen \[({{t}_{1/2}}\]for \[_{6}^{14}C\] is 5000 years) and a freshly cut wood gives 15 counts/min/gm of carbon [AMU (Engg.) 2002]

    A)            \[5.78\times {{10}^{4}}\]years                                         

    B)            \[9.85\times {{10}^{4}}\]years

    C)            \[7.85\times {{10}^{3}}\]years                                         

    D)            \[0.85\times {{10}^{4}}\]years

    Correct Answer: C

    Solution :

            \[t=\frac{2.303}{0.693}\times 5000\times \log \frac{15}{5}\]                    \[=\frac{2.303}{0.693}\times 5000\times \log 3=7927=7.92\times {{10}^{3}}yrs\text{.}\]


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