A monochromatic light is incident on the plane interface AB between two media of refractive
Channel: Doubtnut
Date: 2020-07-26

A monochromatic light is incident on the plane interface AB between two media of refractive indices `mu_(1)` and `(mu_(2)gtmu_(1))` at an angle of incidence `theta` as shown in Fig.   The angle `theta` is infinitesimally greater than the critical angle for the two media so that total internal reflection takes place. Now, if a transparent slab DEFG of uniform thickness and of refractive index `mu_(3)` is introduced on the interface (as shown in the figure), show that for any value of `mu_(3)` all light will ultimately be reflected back into medium II.  img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/BMS_V04_C01_S01_042_Q01.png" width="80%"