Question

A white light source is placed in a denser medium. For a ray of white light, shown in the diagram below, the angle of incidence equals the critical angle for green color light. Which colors are reflected back?

• A. Violet
• B. Indigo
• C. Yellow
• D. Blue

Answer 1

Answer: (A), (B), (D)

The correct options are
A Violet
B Indigo
D Blue

(i) When white light passes through a prism, it undergoes dispersion. Here violet, indigo and blue colors are more deviated than green, yellow, orange and red colours ${\mu }_{violet}>{\mu }_{red}$.
(ii) Red, orange and yellow pass into rarer medium; blue, indigo and violet reflect back into denser medium.