Question

Three transparent media of refractive indices $\mu_{1} \mu_{2},\mu_{3 },$, respectively, are stacked as shown below. $A $ ray of light follows the path shown. No light enters the third medium

Then

• A. $\mu_{1}< \mu_{2}<,\mu_{3},$
• B. $\mu_{2}< \mu_{1}<,\mu_{3},$
• C. $\mu_{1}< \mu_{3}<,\mu_{2},$
• D. $\mu_{3}< \mu_{1}<,\mu_{2},$

Answer 1

Answer: (D)

In first incidence, light ray is bends towards normal so, it must be going into a denser medium.

i e. $\mu_{2} > \mu_{1}$
As, in second incidence, no light goes into third medium so, total internal reflection takes place at second incidence.
Hence, light is going from a denser to a rare medium,
i.e $\mu_{2} > \mu_{3}$
Also $\mu_{1}\ne \mu_{3}$ and $\mu_{1}> \mu_{3}$, because there is no emergent light.
Hence, $\mu_{3}< \mu_{1}<\mu_{2}$ is correct order.