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Nuclei — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsNuclei1 Mark
MCQ
In one average$-$life:
  • A
    Half the active nuclei decay.
  • B
    Less than half the active nuclei decay.
  • ✓
    More than half the active nuclei decay.
  • D
    All the nuclei decay.
✓

Answer

Correct option: C.
More than half the active nuclei decay.
The average life is the mean life time for a nuclei to decay.
It is given as
$\tau=\frac{1}{\lambda}=\frac{\text{T}_{\frac{1}{2}}}{0.693}$
Here, $\tau,\lambda$ and $\text{T}_{\frac{1}{2}}$ are the average life, decay constant and half life$-$time of the active nuclei, respectively. The value of the average lifetime comes to be more than the average lifetime. Therefore, in one average life, more than half the active nuclei decay.

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