Effect of rotating polarizer on intensity of transmitted light

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Homework Help Overview

The discussion revolves around the effect of a rotating polarizer on the intensity of transmitted light. The original poster presents a scenario involving plane polarized light incident on a polarizer, with specific intensity values provided.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the relationship between the incident and transmitted intensities, questioning the application of relevant laws for polarizers. There are attempts to resolve the problem using vector resolution and references to specific equations related to polarizers.

Discussion Status

The discussion is ongoing, with participants providing insights into the laws governing polarizers, including references to Malus's Law. Some participants express confusion regarding the calculations and the expected outcomes, indicating a need for further clarification.

Contextual Notes

There are indications of uncertainty regarding the correct application of the polarizer laws and the interpretation of intensity changes upon rotation. The original poster's calculations and assumptions are also under scrutiny.

NihalRi
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Homework Statement



Plane polarised is incident normally on a polerizer which can rotate in plane perpendicular to light. The intensity of of incident light is 8W[m][/-2] and transmitted intensity is 2W[m][/-2] if polerizer is rotated 90 deg what is the new transmitted intensity

Homework Equations

The Attempt at a Solution


Root of (8 squared minus 2 squared)=root 60
Resolving vectors?
Answer was 6W[m][/-2]
Which is just eight minus two, help? I don't know why
 
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What is the law for polarizers? In other words, what relevant equation applies to polarizers?
 
gneill said:
What is the law for polarizers? In other words, what relevant equation applies to polarizers?
Transmitted intensity = incident intensity times cosine there
Where theta is the angle between the direction of the polerizer and the polarised light
 
NihalRi said:
Transmitted intensity = incident intensity times cosine there
Where theta is the angle between the direction of the polerizer and the polarised light
Close, but not quite: the cosine should be squared. Look up "Law of Malus" (or Malus's Law).
 
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