Starting with a sample of pure ^{66}Cu , 7/8 of it decays into Zn in 15 min . The corresponding half-­life is

  • Option 1)

    5 minutes

  • Option 2)

    7\frac{1}{2} minutes

  • Option 3)

    10 minutes

  • Option 4)

    14 minutes

 

Answers (1)

As we learnt in

Number of nuclei after disintegration -

N=N_{0}e^{-\lambda t} or A=A_{0}e^{-\lambda t}

- wherein

Number of nucleor activity at a time is exponentional function

 

 N=\frac{N_{0}}{8}=\frac{N_{0}}{2^{t/T_{1/2}}}

Hence   t = 3 T1/2

given t = 15 min.

\Rightarrow\ \;T_{1/2}=5 min.

Correct option is 1.


Option 1)

5 minutes

This is the correct option.

Option 2)

7\frac{1}{2} minutes

This is an inocrrect option.

Option 3)

10 minutes

This is an inocrrect option.

Option 4)

14 minutes

This is an inocrrect option.

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