Question

A ray of light travelling through air, falls on the surface of a glass slab at an angle i. It is found that the angle between the reflected and refracted ray is 90°. If the speed of light in glass is 2 x 10⁸ m/s find the angle of incidence. (C = 3 x 10⁸ m/s)
(Ans : i = 56°19')

Answer 1

so this question is solved like this :

Answer 2

Hey Kunica

◆ Answer -

i = 56.31°

● Explanation -

# Given -

v = 2×10^8 m/s

# Solution -

Here, its given that reflected ray & refracted ray make 90° to each other. That is

i + r = 90

r = 90 - i

Putting this in Snells law -

n = sini/sinr = c/v

sini/sin(90-i) = c/v

sini/cosi = (3×10^8)/(2×10^8)

tani = 1.5

i = taninv(1.5)

i = 56.31°

Therefore, angle of incidence is 56.31°.