A triangular prism of small apex angle A is used in a laboratory to study the spread…
PHYSICS · Multi-part · CBSE · Physics · The Human Eye and the Colourful World · The Human Eye and the Colourful World
Problem
A triangular prism of small apex angle A is used in a laboratory to study the spread of colours produced when white light passes through it.
(i) Explain the physical meaning of the term “dispersive power” of the prism material.
(ii) For two different glass materials X and Y, the angular deviations produced by the same apex-angle prism are as follows:
Material X : deviation for violet = 3.4°, deviation for red = 2.6°
Material Y : deviation for violet = 3.2°, deviation for red = 2.8°
Both prisms give a mean deviation of 3.0° for the green ray. Determine which material has the larger dispersive power and justify your answer with suitable calculations.
(iii) State any one optical application where a material of low dispersive power is preferred and briefly explain why.