Question

Suppose you are using total internal reflection to make an efficient corner reflector - that is, a material shaped so that the light is reflected back towards its source. For example, each one of the prisms in the binocular shown is a corner reflector.

θ = 32 °

If there is air outside and the incident angle at the first glass-air interface is 32° with respect to the normal, what must be the minimum index of refraction, n_min, of the material from which the reflector is made, to ensure that total internal refraction occurs at the first interface?

Answer 1

The concept used is of total internal reflection , initially i give you a example and tell you how to calculate the minimum refractive index of the material , as we can see if we assume n2=2 then critical angle comes out to be 30 degree which means light woould get totally reflected for angle of incidence beyond 30 degree and in that our 32 degree also come , but in question minimum refractive index is asked so for i that i need to equate the angle of incidence equal to critical angle and it gives me the minimum value refractive index less than the initial value ( less than 2 ) , both answers are correct but according to question we have to find out the minimum value of the refractive index of the material .so our second answer is right which is less than 2 .

kindly upvote my answer , if you like , by clicking on the like button.