The half-life period of a radioactive element $X$ is the same as the mean lifetime of another radioactive element $Y$. Initially, both of them have the same number of atoms. Then:

  • A
    $X$ and $Y$ have the same decay rate initially.
  • B
    $X$ and $Y$ decay at the same rate always.
  • C
    $Y$ will decay at a faster rate than $X$.
  • D
    $X$ will decay at a faster rate than $Y$.

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