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BHU PMT BHU PMT (Mains) Solved Paper-2010

  • question_answer
    A sample of rock from the moon contains equal number of atoms of uranium and lead (\[{{t}_{1/2}}\]for\[U=4.5\times {{10}^{9}}yr\]). The age of the rock would be

    A)  \[4.5\times {{10}^{9}}yr\]                           

    B) \[9.0\times {{10}^{9}}yr\]

    C)  \[13.5\times {{10}^{9}}yr\]        

    D) \[2.25\times {{10}^{9}}yr\]

    Correct Answer: A

    Solution :

                     Equal no. of atoms of U and Pb means half of U has disintegrated. \[\therefore \]Time taken\[={{t}_{1/2}}=4.5\times {{10}^{9}}yr\]


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