Is the Book Wrong About Total Internal Reflection and Snell's Law?

Click For Summary
SUMMARY

The discussion centers on the interpretation of Snell's Law and the behavior of light during refraction. According to Snell's Law, represented as n1sin(theta1) = n2sin(theta2), the angle of refraction increases as the angle of incidence increases, confirming that the book's explanation is correct. The frequency of light remains constant when transitioning between media, while the speed and wavelength change to maintain the relationship defined by the equation velocity = frequency × wavelength. A practical approach to understanding these concepts includes creating a table of values to visualize the relationships.

PREREQUISITES
  • Understanding of Snell's Law and its mathematical representation
  • Familiarity with the concepts of wave speed, frequency, and wavelength
  • Knowledge of the refractive indices of different media
  • Basic principles of light behavior during refraction
NEXT STEPS
  • Study the derivation and applications of Snell's Law in optics
  • Explore the relationship between wave speed, frequency, and wavelength in different media
  • Learn about the refractive indices of common materials and their impact on light behavior
  • Practice creating tables to visualize the effects of changing angles and indices on refraction
USEFUL FOR

Students of physics, educators teaching optics, and anyone interested in understanding the principles of light refraction and wave behavior in different media.

AznBoi
Messages
470
Reaction score
0
As the angle of incidence increases, the angle of refraction becomes larger.

Should the underlined word be decreases? why? I think I've found a mistake in the book because according to snell's law of refraction n1sin(theta)1=n2 sin(theta)2 right? If n1>n2 then (theta)1<(theta)2

Wait, I don't know now. I think I'm getting mixed up with angles and indices. =[ Help please.
 
Physics news on Phys.org
Is there any easy way to remember the relation of n=c/v, snails law, and how the refracted angle behaves when n1>n2 or vice versa?
 
Also, how come the frequency of light doesn't change as is passes from one medium to another? How do you know if the speed of the wave, frequency, or wavelength changes? I know that the speed of sound/light changes when it goes through another medium but how do you know if frequency or wavelength change or stays constant? Is there a rule for this concept? Thanks
 
bump. help anyone please?
 
AznBoi said:
As the angle of incidence increases, the angle of refraction becomes larger.

Should the underlined word be decreases? why? I think I've found a mistake in the book because according to snell's law of refraction n1sin(theta)1=n2 sin(theta)2 right? If n1>n2 then (theta)1<(theta)2

Wait, I don't know now. I think I'm getting mixed up with angles and indices. =[ Help please.


The book is correct. The angle of the refracted ray will bend away from the normal for increasing values of incident angle, in both cases of n1>n2 and n1<n2. Perhaps work out a table of values to see for yourself.
 
I will try to explain this, as I learned it. Maybe someone can fill it in a bit.
If you think of the wave fronts being parallel to the boundary between the two media, the number of wave fronts (so frequency) passing a point in medium 1 must be the same as the number of wave fronts passing a point in medium 2. If this were not true, wave fronts would be piling up or being destroyed or whatever and there is no physical mechanism for that to happen. So since the speed changes, the wavelength must change, to keep the relation of velocity = frequency*wavelength valid (in both media).

Hopefully that helps a bit.
 

Similar threads

Optics: refraction and reflection
  • · Replies 1 ·
Replies
1
Views
2K
Total Internal Reflection and Transmitted Wavelength
  • · Replies 1 ·
Replies
1
Views
950
Question about reflectivity and maximization of energy reflected
  • · Replies 1 ·
Replies
1
Views
1K
How can I find the minimum index of refraction?
  • · Replies 7 ·
Replies
7
Views
7K
When can internal reflection be used to find the index of refraction
  • · Replies 4 ·
Replies
4
Views
2K
Equations for total internal reflection
  • · Replies 9 ·
Replies
9
Views
3K
Maximum critical angle for total reflection?
  • · Replies 5 ·
Replies
5
Views
3K
Multiplayer Refraction, Incident Angle
  • · Replies 3 ·
Replies
3
Views
11K
Prove n1<N<n2 for effective index N....
  • · Replies 3 ·
Replies
3
Views
2K
What is the relationship between critical angle and negative refractive index?
  • · Replies 6 ·
Replies
6
Views
2K