The value of the acceleration due to gravity is g_1 at a height h =R/2 ( R = radius of the earth) from the surface of the earth. It is again equal to…

The value of the acceleration due to gravity is $\displaystyle \mathrm{g}_1$ at a height $\displaystyle \mathrm{h}=\frac{\mathrm{R}}{2}$ ( $\displaystyle \mathrm{R}=$ radius of the earth) from the surface of the earth. It is again equal to $\displaystyle \mathrm{g}_1$ at a depth d below the surface of the earth. The ratio $\displaystyle \left(\frac{d}{R}\right)$ equals :