Question

A double convex lens of `+ 5 D` is made of glass of refractive index `1.5` with both faces of equal radii of curvature. Find the value of curvature.

Answer 1

`P = + 5D, mu = 1.5`,
`R_(1) = R, R_(2) = -R`
From `(1)/(f) = (mu - 1)((1)/(R_(1)) - (1)/(R_(2)))`
`5 = (1.5 - 1)((1)/(R ) + (1)/(R )) = (1)/(R )`
`R = (1)/(5)m = 20 cm`