White light is incident on the interface of glass and air as shown in the figure. If the green light is just totally internally reflected then which of the following does the emerging ray in the air contain?

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

yellow, orange, red

violet, indigo, blue

all colours

all colours except green

answer is A.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

If the green light is just totally internally reflected then the emerging ray in the air contains yellow, red, orange.
In the

VIBGYOR

sequence, the wavelength gets longer. Cauchy's formula states that as the wavelength increases, the refractive index (μ) decreases. As a result, the refractive index will rise in

ROYGBIV

order. Thus, the critical angle

θ_{C}

will rise in the same

VIBGYOR

order.
Critical angle

θ_{C} ​ = si n^{- 1} (\frac{1}{μ})

The incidence angle for green light is almost exactly equal to the critical angle. The critical angle will be greater than the incidence angle for yellow, orange, and red. These hues will consequently show up at the glass-air interface. Red, orange, yellow, green, blue, and violet make up the six primary colours that make up the spectrum of white light, which are arranged in a specific order. If the green light is simply entirely internally reflected, yellow, orange, and red make up the emerging ray in the atmosphere.

Watch 3-min video & get full concept clarity