The graph between 1 u and 1 v 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 1 . 5 and its both the surfaces have same radius of curvatures R . The value of R will be _____ cm . (Where u = object distance, v = image distance)

Step-by-step solution

For point B ,   1 u = - 0 . 10   cm - 1 ,   1 v = 0 ∴ Thus, u = - 10   cm ,   v = ∞ Using lens formula, 1 f = 1 v - 1 u = 0 - - 10 ⇒ f = 10   cm Now, using Lens maker's formula, 1 f = μ - 1 1 R 1 - 1 R 2 , where, μ is refractive index of lens. ⇒ 1 10   cm = 1 . 5 - 1 2 R = 1 R ⇒ R = 10   cm