Physics - Modern Physics Question with Solution | TestHub

Two radioactive materials $X_1$ and $X_2$ have decay constants $5\lambda$ and $\lambda$ respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of ${\mathrm{X}}_1$ to that of $X_2$ will be $\frac{1}{e}$ after a timeNEET 2008 (Mains)