# MCAT Physical : Polarization

## Example Questions

### Example Question #1 : Polarization

Unpolarized light passes through three polarizing filters. The angle between the first and second filters is 45o. The angle between the second and third filters is also 45o. What is the relationship between the intensity of light emerging from the third filter, , and the incident intensity,  ?

No light passes through the third filter

Explanation:

Going through the first filter, the intensity of initially unpolarized light decreases by 1/2, so . For each filter after the first, the intensity decreases by an additional factor of , where  is the angle between adjacent polarizers. So, after the second filter, we have can see that . Similarly, after the third filter, we have .

### Example Question #24 : Waves

Unpolarized monochromatic light passes through a single polaroid filter, oriented horizontally. It then encounters a second filter that is oriented vertically. Which of the following statements is true of the resulting light?

The emerging light has one half of the incident intensity and is polarized vertically

The emerging light has one half the incident intensity and is polarized at

The emerging light has one-fourth the incident intensity and is polarized vertically

The light is entirely blocked

The emerging light has the same intensity, but is now polarized at

The light is entirely blocked

Explanation:

The first filter polarizes the light horizontally, only allowing light to pass if it is oscillating horizontally. This would decrease the intensity by one-half.

The second filter would polarize the light vertically, only allowing light to pass if it oscillates vertically. The first filter, however, has already blocked all non-horizontal waves, including any vertical waves; thus, there are no remaining waves that can pass through the vertical filter. The light is fully blocked by this combination.

### Example Question #25 : Waves

Each of the following types of waves experience polarization except __________.

electromagnetic waves

transverse waves

light waves

sound waves