Physics - Modern Physics Question with Solution | TestHub

Two radioactive substances $\mathrm{A}$ and $\mathrm{B}$ have decay constants $5\lambda$ and $\lambda$ respectively. At $t=0$ they have the same number of nuclei. The ratio of number of nuclei of A to those of $\mathrm{B}$ will be $(1/e{)}^2$ after a time interval.NEET 2007