Isotope A has a decay constant of $0.861 \mathrm {~s} ^ { - 1 }$ and isotope B has a decay constant of $0.627 \mathrm {~s} ^ { - 1 }$. Which isotope has a longer mean life (time constant)?

Question

Quizplus · Accepted Answer

The mean life (time constant) of an isotope is the inverse of its decay constant. Since isotope B has a lower decay constant ($0.627 \mathrm {~s} ^ { - 1 }$) compared to isotope A ($0.861 \mathrm {~s} ^ { - 1 }$), it has a longer mean life.

Isotope a Has a Decay Constant Of 0.861 s−10.861 \mathrm {~s} ^ { - 1 }0.861 s−1

Isotope a Has a Decay Constant Of $0.861 \mathrm {~s} ^ { - 1 }$