Question

Water has a refractive index 4/3 at what angle of incidence should a ray be incident on water air interface (from water) to suffer total internal reflection?

Answer 1

Answer:

So for angles of incidence greater than 48.6-degrees, TIR occurs. But 48.6 degrees is the critical angle only for the water-air boundary.

Answer 2

Answer:

Given that refrective index=4/3

Let critical angle=C

According to Snell's law

C=sin^-1(1/refrective index)

C=sin^-1(3/4)

C=sin^-1(0.75)

C=48.59°