The graph between 1/u and 1/(ν) for a thin convex lens in order to determine its focal length is plotted as shown in the figure. The refractive index…

The graph between $\displaystyle \frac{1}{u}$ and $\displaystyle \frac{1}{\nu}$ for a thin convex lens in order to determine its focal length is plotted as shown in the figure. The refractive index of lens is $\displaystyle 1.5$ and its both the surfaces have same radius of curvature $\displaystyle R$. The value of $\displaystyle R$ will be \_\_\_\_ cm. (where $\displaystyle u=$ object distance, $\displaystyle \nu=$ image distance)