Question

At what angle is the sun above the horizon if its light is found to be completely polarized when light in air is reflected from the top surface of a slab of glass (n_air = 1 and n_glass = 1.55)?

Group of answer choices

32.8°

57.2.°

49.8°

52.7°

40.2°

Answer 1

The angle of incidence in this case is called Brewster’s angle and is denoted by i​​​​​b.

The relation with incident angle i​​​​​​b is given by µ = tan i​​​​​​b

Where μ is refractive index of glass μ= 1.55.

Now use condition to find Brewsters angle ib.

1.55 = tan i​​​​​​b

So i​​​​​​b = 57.17

Now sun angle above the horizon is ∅

Then use condition

∅ = 90 - i​​​​​​b

∅ = 90 - 57.2

∅ = 32.8°

So sun is at angle 32.8° above the horizon.