The difference between the radii of 3^rd and 4^th orbits of Li^2+ is Δ R_1. The difference between the radii of 3^rd and 4^th orbits of He ^+ is Δ…

The difference between the radii of $\displaystyle 3^{\text {rd }}$ and $\displaystyle 4^{\text {th }}$ orbits of $\displaystyle \mathrm{Li}^{2+}$ is $\displaystyle \Delta \mathrm{R}_1$. The difference between the radii of $\displaystyle 3^{\text {rd }}$ and $\displaystyle 4^{\text {th }}$ orbits of He $\displaystyle { }^{+}$is $\displaystyle \Delta R_2$. Ratio $\displaystyle \Delta R_1: \Delta R_2$ is :