Size of a light beam before and after Refraction

  • Context: Undergrad 
  • Thread starter Thread starter csirvi
  • Start date Start date
  • Tags Tags
    Beam Light Refraction
Click For Summary

Discussion Overview

The discussion centers on the size of a light beam before and after refraction from a medium, exploring whether the size remains the same or changes. Participants consider mathematical expressions related to this phenomenon and raise questions about the physical implications of changes in beam width and angle of deviation.

Discussion Character

  • Exploratory
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants question whether the size of the light beam is the same before and after refraction, seeking mathematical proof for their assertions.
  • One participant notes that the beam does not appear to be the same size after refraction, suggesting a visual discrepancy.
  • Another participant raises a question about the physical possibility of a change in beam width while the angle of deviation remains the same, indicating a need for clarification on this relationship.
  • Several participants request diagrams or pictures to better illustrate the situation being discussed.
  • There is a discussion about the definition of beam width and its relation to the angles involved in refraction, with some participants questioning the relevance of the angles used in calculations.

Areas of Agreement / Disagreement

Participants express differing views on whether the size of the light beam changes after refraction, and the discussion remains unresolved regarding the relationship between angle of deviation and beam width.

Contextual Notes

Participants have not reached a consensus on the definitions of beam size and width, nor have they resolved the mathematical relationships involved in the discussion.

csirvi
Messages
11
Reaction score
0
The size of light beam is same or different before and after refraction from a medium. If same then why we can not prove from mathematical expression. If not same why?
 
Science news on Phys.org
csirvi said:
Summary:: The size of light beam is same or different before and after refraction from a medium. If same then why we can not prove from mathematical expression. If not same why?

The size of light beam is same or different before and after refraction from a medium. If same then why we can not prove from mathematical expression. If not same why?
Doesn't look the same size to me...

https://cdn3.vectorstock.com/i/1000...rism-ray-rainbow-spectrum-vector-22696987.jpg

1590153600288.png
 
  • Like
Likes   Reactions: davenn and csirvi
Its helpful. . One more question is that if we take single color then the angle of deviation is same but also width of beam after refraction changes mathematically how that is physically possible ?
 
Can you post a picture or diagram of the situation you are asking about? Thanks. :smile:
 
Screenshot_20200522-214642.jpg
 
csirvi said:
then the angle of deviation is same but also width of beam after refraction changes mathematically
Does it? The width of the beam is the distance along a perpendicular to the direction of travel. Look carefully at the angles that you're taking the cosine of... are these what you want?
 
Nugatory said:
Does it? The width of the beam is the distance along a perpendicular to the direction of travel. Look carefully at the angles that you're taking the cosine of... are these what you want?
See width represent soze of beam yes that perpendicular to the Direction of travel.
My question is when the deviation angle same why the width is variable
 
berkeman said:
Can you post a picture or diagram of the situation you are asking about? Thanks. :smile:
Posted the image.
 
berkeman said:
Can you post a picture or diagram of the situation you are asking about? Thanks. :smile:
Screenshot_20200522-214642.jpg
 

Similar threads

Graduate Critical angle (symmetry of refraction) confusion
  • · Replies 5 ·
Replies
5
Views
3K
High School Help with refraction of light
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad Prism Spectrometer Objective: Optics Question
  • · Replies 9 ·
Replies
9
Views
3K
Undergrad Outer layer refractive index - total internal refection on waveguide
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Why do we use low-coherence light in Optical Coherence Tomography?
  • · Replies 1 ·
Replies
1
Views
3K
High School How to build a simple polarization filter
  • · Replies 11 ·
Replies
11
Views
3K
Graduate Mach Zehnder Interferometer Interference fringes issue
  • · Replies 10 ·
Replies
10
Views
3K
Undergrad How can I derive this relation from Snell's law?
  • · Replies 1 ·
Replies
1
Views
2K
High School Refraction of Light: Myth or Reality?
  • · Replies 41 ·
2
Replies
41
Views
5K
Graduate 180 degree phase shift of reflected light
  • · Replies 2 ·
Replies
2
Views
3K