The focal length of a thin convex lens for red and blue rays are 100 cm and 96 . 8 cm respectively. Then, the dispersive power of the material of the lens is

Step-by-step solution

Dispersive power is ratio of angular dispersion and mean deviation. It can be written in terms of focal length as, ω = f r - f b f y Here f r = 100   cm f b = 96 . 8   cm f y = f b × f r = 96 . 8 × 100 ≈ 98 . 34   cm ∴ Dispersive power ω = f r - f b f y = 100 - 96 . 8 98 . 34 ≈ 0 . 0325 Hence, the dispersive power of the material of the lens is 0 . 0325 .