2. Questions Bank
  3. JEE Main & Advanced
  4. Chemistry
  5. Surface & Nuclear Chemistry / भूतल और नाभिकीय रसायन

JEE Main & Advanced Chemistry Surface & Nuclear Chemistry / भूतल और नाभिकीय रसायन Question Bank Rate of decay and Half-life

  • question_answer
    The half-life of a radioisotope is four hours. If the initial mass of the isotope was 200 g, the mass remaining after 24 hours undecayed is                                     [AIEEE 2004]

    A)                 3.125 g 

    B)                 2.084 g

    C)                 1.042 g 

    D)                 4.167 g

    Correct Answer: A

    Solution :

               \[\frac{N}{{{N}_{o}}}={{\left( \frac{1}{2} \right)}^{\frac{T}{{{t}_{1/2}}}}}\]; \[\frac{N}{200}={{\left( \frac{1}{2} \right)}^{\frac{24}{4}}}\]; \[\frac{N}{200}={{\left( \frac{1}{2} \right)}^{6}}\]                                 \[N=\frac{200}{64}=3.125\,g\]


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