Abeam of unpolarized light in air strikes a flat piece of glass at an angle of incidence of 54.2 degrees. if the reflected beam is completely polarized, what is the index of refraction of the glass?
a. 1.60
b. 1.39
c. 1.52
d. 2.48

correct option is B. 1.39

Explanation:

given data

angle of incidence (θ) = 54.2 degrees

to find out

index of refraction of the glass

solution

we know that here reflected beam is completely polarized

so angle of incidence = angle of polarized    1

for reflective index we apply here Brewster law that is

μ = tan(θ)     2

put here θ value we get

μ = tan(54.2)

μ = 1.386

so correct option is B. 1.39

1.386

Explanation:

Angle of incidence, i = 54.2°

Let n be the refractive index of glass.

According to the Brewster's law

n = tan ip

where, ip is the polarising angle.

n = tan 54.2°

n = 1.386

Thus, the refractive index of glass is 1.386.