Lesson: Polarization of Light Physics • 9th Grade

In this lesson, we will learn how to describe the changes to the polarization angle and intensity of light waves produced by polarizing filters.

Lesson Plan

Students will be able to

identify the polarization axis of unpolarized light transmitted through a polarizer,
identify the polarization axis of plane-polarized light transmitted through a polarizer,
qualitatively describe the effect on the intensity of polarized light that is transmitted through a polarizer,
relate the intensity of plane-polarized light incident on and transmitted through a polarizer with a polarization axis at an angle to the polarization axis of the incident light, using the equation ,
relate the angle, , of reflected light that is reflected from a boundary between media with refractive indices and , traveling in the medium of index , at which the reflected light is completely polarized to the refractive indices of the media, using the equation .

Lesson Worksheet

Q1:

Unpolarized light traveling in air that has a refractive index of 1 reflects from a film of oil. The angle from the normal to the surface of the oil of reflected light that is completely polarized is . What is the refractive index of the oil? Give your answer to one decimal place.

Q2:

Unpolarized light passes through two polarizers that have polarization axes apart from each other. The intensity of the light after it passes through both polarizers is 0.15 W/m². What is the initial intensity of the light?

Q3:

Unpolarized light passes through two polarizers. The light has an initial intensity of 1.8 W/m². The intensity of the light after it passes through both polarizers is 0.85 W/m². What is the angle between the polarization axes of the polarizers?