Question

Example
A rectangular glass wedge (prism) is immersed in water
as shown in figure E-a. For what value of angle a, will the
beam of light, which is normally incident on AB, reach AC
entirely as shown in figure E-b. Take the refractive index of
water as 4/3 and the refractive index of glass as 3/2.
explain in detail plzzz​

Answer 1

Please read this answer & it was helpful to me as well...

Answer 2

Answer: a is greater than C=62°30'

EXPLANATION:-

From the geometry of figure E-b it is clear that the angle of incidence on side BC is equal to a (dotted line is normal drawn at point of incidence). The ray should undergo TIR (total internal reflection) to reach AC. For occurrence of TIR, the value of "a" must be greater than Critical angle (C) at the interface.

From the condition, a>C------(1)

We know , sinC=1/n12. ------(2)

n12 = n1/n2 = (3/2)/(4/3) = 9/8

From equation 2, we get

sinC = 8/9 ----- C = 62°30'

Hence "a" is greater than C = 62°30'