How Does Malus' Law Explain Light Transmission Through Polarizers?

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Homework Help Overview

The discussion revolves around the application of Malus' Law in understanding light transmission through polarizers. Participants are examining a scenario involving two polarizers oriented at an angle to each other and the behavior of plane-polarized light passing through them. Additionally, there is a question regarding the width of the first-order spectrum produced by a grating when white light is incident on it.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants are attempting to determine the initial polarization direction of light based on the percentage of light transmitted through the polarizers. There are inquiries about the application of Malus' Law, specifically regarding the variables involved in the formula. Some participants express confusion about how to apply the law to their specific problems and seek guidance on what values to use for intensity.

Discussion Status

The discussion is ongoing, with participants sharing their attempts and seeking clarification on the concepts involved. Some guidance has been offered regarding the use of Malus' Law, and there is an acknowledgment of the need for further exploration of the problem setup. Multiple interpretations of the questions are being considered, and participants are encouraged to share their work for further assistance.

Contextual Notes

Participants have expressed a lack of clarity regarding the initial conditions and parameters necessary to apply Malus' Law effectively. There is also mention of the need for specific numerical answers, which may indicate constraints imposed by homework requirements.

Evergreen
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need help with capa questions...

Two polarizers are oriented at 35.7o to each other and plane-polarized light is incident on them. If only 11.9 percent of the light gets through both of them, what was the initial polarization direction of the incident light?


White light containing wavelengths from 391 nm to 758 nm falls on a grating with 7770 lines/ cm. How wide is the first-order spectrum on a screen 2.40 m away?




just two questions, i have no clue... :redface:
 
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Evergreen said:
Two polarizers are oriented at 35.7o to each other and plane-polarized light is incident on them. If only 11.9 percent of the light gets through both of them, what was the initial polarization direction of the incident light?
Are you familiar with Malus' Law? It says that if linearly polarized light passes through a polarizer, the intensity of the light transmitted is I = Iincidentcos2(θ), where θ is the angle between the polarization direction of the incident light and the polarization axis (transmission axis) of the polarizer.
White light containing wavelengths from 391 nm to 758 nm falls on a grating with 7770 lines/ cm. How wide is the first-order spectrum on a screen 2.40 m away?
Take a peek at these threads:
https://www.physicsforums.com/showthread.php?t=16902
https://www.physicsforums.com/showthread.php?t=17047
 
i need a numeric answer, for the second question that I am posting, i did use a similar method, but my answer is still wrong
 
Evergreen said:
i need a numeric answer, for the second question that I am posting, i did use a similar method, but my answer is still wrong
Show your work and I'll take a look.
 
Last edited:
Doc Al said:
Are you familiar with Malus' Law? It says that if linearly polarized light passes through a polarizer, the intensity of the light transmitted is I = Iincidentcos2(θ), where θ is the angle between the polarization direction of the incident light and the polarization axis (transmission axis) of the polarizer.
QUOTE]
I have a question on this also...
I am fairly new with this material, and I know that I am trying to find theta, but what do I plug in for I and Io? Is there any good reading online for this?
 
Law of Malus

PrettyMz4Christ said:
I have a question on this also...
I am fairly new with this material, and I know that I am trying to find theta, but what do I plug in for I and Io?
That depends on what you are given in the problem. If you have a specific problem, post it and your work and I'll take a look. (You might want to start a new thread.)

I give a brief description of Malus' law in my earlier post.
Is there any good reading online for this?
Do a search on Malus' Law and you'll find plenty. Here's one place to start: http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/polcross.html#c3

Welcome to PF!
 

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