Question

A beam of white light is incident on glass air interface from glass to air such that green light just suffers total internet reflection. The colors of the light which will come out to air are

• A. Violet, Indigo, Blue
• B. All colors except green
• C. Yellow, Orange, Red
• D. White light

Answer 1

Answer: (C)

$\begin{array}{c}\begin{array}{c}VIBGYOR\\ \uparrow \\ \text{Green light suffers total internal reflection}\\ \text{The refractive index of the material}\\ \text{of prism increases with the decrease}\\ \text{in the wavelength of light.}\\ {\mu }_2>{\mu }_B>{\mu }_9>{\mu }_y>{\mu }_0>{\mu }_R\end{array}\\ \text{In case of prism}\end{array}$

$\begin{array}{c}\mu \sin c=1\\ \text{where}\mu =\text{refractive index of prism}\\ c=\text{critical angle}\\ \text{in case of green}\\ \sin c=\frac{1}{M_9}\\ \text{for TIR}\\ \mu \sin c>1\\ \text{so Yellow, orange, red are the required.}\\ \text{colors}\\ \text{option}c\text{is correct.}\end{array}$