Why if a ray pass though different materials its direction changes?

AI Thread Summary
When light passes through different materials, its direction changes due to the varying speeds of propagation in each medium. The wave front of light is perpendicular to its direction of travel, and when it encounters a new medium, one edge enters first, leading to a change in velocity. This difference in speed causes the wave front to rotate, resulting in a change in the angle of the ray. The phenomenon is explained by Snell's Law, which describes how light refracts at the boundary between two materials. Understanding this principle is essential for explaining optical behaviors in various contexts.
scientifico
Messages
181
Reaction score
0
Hello, why if a ray pass though different materials its direction changes ? couldn't its propagation speed just increase or decrease without having to change the angle ?

Thank you
 
Last edited by a moderator:
Physics news on Phys.org


The way I was taught is that light has a wave front that is perpendicular to the direction of travel. When the wave front hits a different medium, one edge of the wave front enters the medium first and its velocity changes. This causes the wave front to rotate and change the direction of the ray.
 
Thread 'Gauss' law seems to imply instantaneous electric field'

Thread 'Gauss' law seems to imply instantaneous electric field'

Imagine a charged sphere at the origin connected through an open switch to a vertical grounded wire. We wish to find an expression for the horizontal component of the electric field at a distance ##\mathbf{r}## from the sphere as it discharges. By using the Lorenz gauge condition: $$\nabla \cdot \mathbf{A} + \frac{1}{c^2}\frac{\partial \phi}{\partial t}=0\tag{1}$$ we find the following retarded solutions to the Maxwell equations If we assume that...
View full post »

Thread 'Highway: Deriving speed from Doppler shift'

I passed a motorcycle on the highway going the opposite direction. I know I was doing 125/km/h. I estimated that the frequency of his motor dropped by an entire octave, so that's a doubling of the wavelength. My intuition is telling me that's extremely unlikely. I can't actually calculate how fast he was going with just that information, can I? It seems to me, I have to know the absolute frequency of one of those tones, either shifted up or down or unshifted, yes? I tried to mimic the...
View full post »

Similar threads

I Does an inductor always create a back EMF?
Replies
14
Views
3K
I Effects of gravity on planetary core structure
Replies
9
Views
3K
I Switching polarizer and analyzer: the order matters -- why?
Replies
4
Views
2K
B How to shoot longer shots in basketball
Replies
20
Views
2K
I Why Bremsstrahlung <20keV for Tungsten?
Replies
17
Views
4K
I Geometry of Cherenkov radiation
Replies
4
Views
1K
B Electric Flux - confused about integrating over a tilted area
Replies
8
Views
2K
I Reasoning for circular/elliptical orbits
2
Replies
58
Views
4K
B Multimode optical fiber, physics beginner help :D
Replies
37
Views
4K
Why is the sinusoidal considered the fundamental frequency?
Replies
22
Views
3K

Hot Threads

Recent Insights

Back
Top