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JEE Main & Advanced Physics Nuclear Physics And Radioactivity Question Bank Radioactivity

  • question_answer
    Plutonium decays with a half-life of 24000 years. If the plutonium is stored for 72000 years, then the fraction of plutonium that remains is                                         [CPMT 1999; MH CET 2003]

    A)            \[\frac{1}{2}\]                      

    B)            \[\frac{1}{3}\]

    C)            \[\frac{1}{4}\]                      

    D)            \[\frac{1}{8}\]

    Correct Answer: D

    Solution :

               \[n=\frac{72000}{24000}=3;\]Now \[\frac{N}{{{N}_{0}}}={{\left( \frac{1}{2} \right)}^{n}}=\frac{1}{8}\]


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