Rotating Polarizers: Find Light Intensity

In summary, the problem involves three linear polarizers perpendicular to the same axis, with natural light arriving at the first one. The second polarizer rotates at a known angular speed, and the first and third polarizers have transmission lines perpendicular between them. The intensity of the final light can be found using Malus law, with one term representing the intensity of light hitting the rotational polarizers and the other term being the last intensity multiplied by cos(ωt), where ω is the angular speed. This results in a product rather than a sum, as the amplitude at each polarizer will get multiplied by something less than 1.
  • #1
kususe
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0

Homework Statement


There are three linear polarizers perpendicular to the same axe.
To the first one natural light arrives. If the second one rotates with angular speed known and the first and third ones have transmission lines perpendicular {between them}, find the intensity of final light in function of angular speed and incident light.

Homework Equations


Malus Law



The Attempt at a Solution



i though that the result was a sum of two terms. One of them is the intensity of light hits the rotational polarizers. And the second one is given by the last intensity multiplied to a `cos` of an angle that i cannot express.
in the first term i thought to express an angle in function of angular speed.
 
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  • #2
The angle should be ωt.
It seems to me it will be a product, not a sum. At each polarizer, the amplitude will get multiplied by something less than 1. Your cos(ωt) sounds good for the second polarizer.
 

FAQ: Rotating Polarizers: Find Light Intensity

What is a rotating polarizer and how does it work?

A rotating polarizer is an optical device that can manipulate the polarization of light. It consists of a polarizing material, such as a sheet of polarizing film, that only allows light waves with a specific orientation to pass through. When the polarizer is rotated, the orientation of the light waves passing through it changes, resulting in a change in the polarization of the light.

How do rotating polarizers affect light intensity?

Rotating polarizers can either increase or decrease the intensity of light depending on the orientation of the polarizer and the incoming light. When the polarizer is aligned with the incoming light, it allows all the light to pass through, resulting in maximum intensity. When the polarizer is perpendicular to the incoming light, it blocks all the light, resulting in minimum intensity.

What are some applications of rotating polarizers?

Rotating polarizers have a wide range of applications in various fields such as photography, microscopy, and astronomy. They are used to reduce glare and reflections, improve contrast and color saturation, and even detect hidden stress patterns in materials.

How do you find the optimal angle for maximum light intensity using rotating polarizers?

The optimal angle for maximum light intensity can be found by rotating the polarizer while measuring the intensity of light passing through it. The angle at which the intensity is at its maximum is the optimal angle. This process can be repeated for different light sources and can also be used to find the angle for minimum intensity.

Can rotating polarizers be used to block out all light?

No, rotating polarizers cannot completely block out all light. Even when the polarizer is perpendicular to the light source, some light can still pass through due to imperfections in the polarizer material. However, the intensity of the light will be greatly reduced.

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