Question

Students have 4 different pairs of sunglasses, each with lenses where the polarization filter is oriented in different directions (indicated by the direction of lines drawn on the lenses below). They are planning to ride rafts down a river on a sunny day where there is lots of glare on the water. Which pair would they want to wear to eliminate the glare from the sun

Answer 1

Answer:

the lens you must select has an angle of 143º measured with respect to the horizontal, this angle is 53º with respect to the vertical.

Explanation:

The glare is caused by the reflection of light in the water, the polarization of the reflected light is polarized in a direction parallel to the surface of the water, the polarization is total for the angles

         n = tan  $\theta_{p}$

         \theta_{p} = tan⁻¹ n

the refractive index for seawater is 1.33

         \theta_{p}= tan⁻¹  1.33

         \theta_{p} = 53º

for this angle the light is totally polarized, for the other angles the polarization is partial.

Based on this, the lenses must eliminate this polarization, so its polarization direction must have 90º with respect to this polarization,

          \theta_{lens} = 53 +90

           \theta_{lens}= 143º

Therefore, the lens you must select has an angle of 143º measured with respect to the horizontal, this angle is 53º with respect to the vertical.

A lens that could work is one that is polarized 45º with respect to the vertical.