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JEE Main & Advanced Chemistry Surface & Nuclear Chemistry / भूतल और नाभिकीय रसायन Question Bank Artificial Transmutation

  • question_answer
    A radioactive isotope has a half-life of 10 years. What percentage of the original amount of it remain after 20 years          [KCET 2001]

    A)                 0             

    B)                 12.5

    C)                 8             

    D)                 25

    Correct Answer: D

    Solution :

           \[{{t}_{1/2}}=10yrs,t=20yrs.\]                    \\[n=\frac{t}{{{t}_{1/2}}}=\frac{20}{10}=2\]                                 \[N=\frac{{{N}_{o}}}{{{2}^{2}}}=\frac{1}{4}{{N}_{o}}=\frac{1}{4}\times 100%\,\text{of}\,{{N}_{\text{o}}}=25\].


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