An innovative physics professor conducts laboratory exercises in the college swimming pool. The professor places a submersible laser under water (n = 1.3) and aims the beam at a block of glass (n = 1.5), which is also under water. At what angle of incidence will the reflected beam be totally polarized?
A) 61°
B) 49°
C) 41°
D) 39°

Question

Quizplus · Accepted Answer

The angle for total polarization can be found using Brewster's law which states that the tangent of this angle is equal to the ratio of the refractive indices of the two materials.

Therefore,

tan θ = n2/n1
tan θ = 1.5/1.3
θ = tan^(-1)(1.5/1.3)
θ ≈ 49°

Therefore, the reflected beam will be totally polarized at an angle of incidence of approximately 49°.

The correct choice is B.

An Innovative Physics Professor Conducts Laboratory Exercises in the College