The half life period of radioactive element ${x}$ is same as the mean life time of another radioactive element $y.$ Initially they have the same number of atoms. Then:
${x}$-will decay faster than ${y}$.
${y}$ - will decay faster than ${x}$.
${x}$ and ${y}$ have same decay rate initially and later on different decay rate.
${x}$ and ${y}$ decay at the same rate always.
The half life period of a radioactive element $X$ is same as the mean life time of another radioactive element $Y$. Initially both of them have the same number of atoms. Then
$1\, Curie $ is equal to
At a given instant, say $t = 0,$ two radioactive substances $A$ and $B$ have equal activates. The ratio $\frac{{{R_B}}}{{{R_A}}}$ of their activities. The ratio $\frac{{{R_B}}}{{{R_A}}}$ of their activates after time $t$ itself decays with time $t$ as $e^{-3t}.$ If the half-life of $A$ is $ln2,$ the half-life of $B$ is
The fraction $f$ of radioactive material that has decayed in time $t$, varies with time $t$. The correct variation is given by the curve
Certain radio-active substance reduces to $25\%$ of its value in $16$ days. Its half-life is ........ $days$