Question

A beam of light consisting of red, green, and blue colors is incident on a right-angled prism. The refractive indices of the material of the prism for the above red, green and blue wavelengths are 1.39, 1.44 and 1.47, repectively. The prism will

A. separate part of the red color from the green and blue colors
B. separate part of the blue color from the red and green colors
C. separate all the three colors from one another
D. not separate even partially any color from the other two colors

Answer 1

Correct Answer - A
For total internal reflection `mu=(1)/(sinC)=(1)/(sin45^(@))=1.414`
i.e., for an angle of incidence of that color will suffere total internal reflection for which the refractive index is less than 1.414.
Therefore, red light will be refracted at interface AB whereas blue and green light will be reflected.