All Questions
Tagged with refraction speed-of-light
216
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Is there a good quantum explanation of refraction? [duplicate]
I'm aware of the classical explanation of refraction which deals with light being a wave that gets "slowed" down while passing from a medium to another. One problem that I have with this ...
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Inconvenience of speed of light in optic fiber
As far as I'm concerned, optic fiber is great in order to transport information quickly using light. Since light needs to undergo total internal reflection every single time it hits the walls of the ...
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2
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Fermat principle: how did they know the speed of light in different mediums?
Pierre de Fermat derived his principle of least time by considering the path that light would take when traveling between two points. He postulated that light would follow the path that minimized the ...
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Why the photons are deflected during the refraction? [duplicate]
From what I learnt, when photons are passing throw a denser environnement with an positive angle (from the atmosphere to water for exemple), they are slow down. But I can't understand how this ...
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Can anyone explain the relationship between the refractive index, the speed, wavelength and angle of a wave?
Can anyone explain the relationship between the refractive index, the speed, wavelength and angle of a wave?
in my book is states that $$n = \frac{v_1}{v_2} = \frac{\sin θ_1}{\sin θ_2} = \frac{λ_1}{...
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Why is $c = \frac{1}{\sqrt{\mu_0 \epsilon_0}}$?
I'm sorry if this is a duplicate but I didn't find my answer. I'm currently studying maxwell's equations and I know that by comparing the wave equation for either the magnetic or the electric field
\...
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Does light accelerate? [duplicate]
If considering the general formula for acceleration, ie.
Δ V/ΔT, we would get zero as the velocity of light is constant and does not change.
However, what about when photons travel through different ...
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2
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On the (variable?) nature of $\epsilon_0$ and $\mu_0$
In electromagnetism, the electric displacement field D represents the distribution of electric charges in a given medium resulting from the presence of an electric field E. Its relation to ...
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When light passes from one medium to another. Depending on the density, it would experience a change in velocity. Why would its vector change as well?
For example, when light passes through water its velocity decreases and refraction occurs. Why? Why is there a change in direction. If I slow down a car I don’t suddenly turn left.
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Speed in a medium
Let's say, that there is medium, where the speed of light is $10^8 \, \rm m/s$. So in that medium if there exists a particle that is moving through without any hindrance what would be the speed limit ...
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Can the refractive index of a medium be negative?(<0)
Recently I was asked in a test what would happen if the refractive index of a medium was negative. Is it possible really? The refractive index is the ratio of the speed of light in a vacuum and ...
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3
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Is it possible to distinguish the type of space according to the speed of light in vacuum? [duplicate]
Why is the speed of light 300 000 km/s? The speed of light is slower in glass, water and diamond. Is the speed of light in water, glass and diamond also absolute? Can we calculate the material such as ...
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What is the speed of light in case of Critical Angle?
When light travels from an optically denser to a rarer medium, it bends away from the normal and at a specific angle of incidence, the angle of refraction is ${90}^{\circ}$. When the angle of ...
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At what speed does information move through the atoms of a rigid object?
How fast does information travel on particles? I thought if you move a iron bar from one end it would take the speed of sound to move its other end. For example, theoretically if you hold an iron bar ...
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Amaterasu particle's secondary particles travel faster than the speed of light?
From this article in The Guardian
When ultra-high-energy cosmic rays hit Earth’s atmosphere, they initiate a cascade of secondary particles and electromagnetic radiation in what is known as an ...
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Why does the different speed of light in different media cause refraction?
Why doesn't light simply go more slowly without bending? Is there a macro phenomenon, say a stream of bullets, that will also bend as it changes from one medium to another or is light somehow unique?
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Is the speed of causality slower in water?
I've recently read that what most people learned to think of as the 'speed of light' is actually the 'speed of causality', and that light just happens to travel at that speed (through free-space.) I'...
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Do photons moving at $c$ slow down when entering a medium or take a longer path and only appear to slow down and what happens to time? [duplicate]
Imagine a photon leaving a vacuum and entering a medium, say, air. I have 2 questions:
Some claim that the photon is slowed by the medium so its speed becomes less than $c$. Is that true or does ...
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Does Color change happen under a prism? [duplicate]
I was watching this video.
It Showed that light ( green ) changes its color to red after incidence of light. I couldn't think of how this happens because light's color is dependent on frequency rather ...
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Relativistic Effects on Electromagnetic Wave Propagation
So for a recent lab I had to calculate the length of a conductor by measuring the time it took a signal to reflect off of the open end. I used the very simple principle of $v=st$ and, knowing that the ...
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Speed of light getting lower in densed medium [duplicate]
In densed medium speed of the light gets lower so in this kind of situation is there anything which can travel quicker than light?
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Why does speed of light relate to the density of the surrounding medium?
Why does the speed of light relate to the refractive index of its surrounding medium while it is a massless electromagnetic wave?
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Cherenkov radiation; hypothetical question
It is explained that Cherenkov radiation is light that emit a particle inside a refractive material when the speed of the emitted light is slower than $c$. So my hypothetical question is what would be ...
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Refraction of light with different wavelengths [closed]
A red light and blue light enter a rectangular glass block normal to its surface at the same time. Strictly speaking, after passing through the block, which pulse exits first?
Should I consider their ...
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How does a refractive index of less than one not violate relativity?
If I am not mistaken, this video says that X-rays travel faster in glass than in a vacuum. Special Relativity says that information can not travel faster than the speed of light in a vacuum, so what ...
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When designing antennas which speed of light should be used?
When calculating "antenna element length" should we use the speed of light in the "medium between transmitter and receiver (antenna)" or the speed of light in the "element ...
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2
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161
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Change of speed of light in case of normal incidence
According to Snell's Law:
$n_1\sin θ_1~=~n_2\sin \theta_2.$
If, $\theta_1 = \theta_2 =~0$
there is no bending but the speed of light changes according to the refractive index.
Is this the case or I am ...
user355398
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2
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Speed of EM Waves
We know that for electromagnetic waves, according to Maxwell's Theory
$$v=\frac{1}{\sqrt{\mu\epsilon}}$$
Now consider an opaque object like say Gold. It has a particular value of permittivity and ...
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Does the intensity of blackbody radiation depend on the speed of light in the medium?
In 1863, in “ON THE CONCENTRATION OF RAYS OF HEAT AND LIGHT, AND ON THE LIMITS OF ITS ACTION”, Clausius wrote in the conclusion:
To harmonize the effects of ordinary radiation, without concentration, ...
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Can a ray of light deviate passing from a rarer to a denser medium deviate beyond the normal?
Is this allowed? Technically, if the difference in the refractive indexes is big enough, and the ray of light has a low wavelength (violet), it should be able to deviate beyond the normal.
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Why does refractive index increase with concentration of the medium?
I learnt that lights decrease velocity in a medium during absorbance and emission of its energy in the charged particles in the medium. From the Beer's law, I read that absorbance is directly ...
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A world where speed of light is slower than regular objects
The subject explains the question.
Any idea of what a universe would be like where speed of light is a lot slower? Like, slower than sound, aeroplane, bullets etc.
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What is the definition of absolute refractive index of a medium?
I know the definition is the ratio of the speed of light in vacuum to the phase velocity of light in the given medium. Here, which color of light do we consider while calculating the ratio? For ...
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Speed of light exiting a prism [duplicate]
When light travels through a medium, even a sparse medium, it slows down from the speed of light in vacuum to the speed of light in that medium.
When that light re-enters a true vacuum, it will resume ...
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2
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Speed of photon
Background:
I originally asked this question
Does a single photon propagate with phase velocity or front velocity through a dispersive material? about the speed of a single photon in a dispersive ...
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2
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Can X-rays travel quicker than visible light in a medium?
I have seen while reading a few books that the refractive index depends on lambda as follows by the Cauchy equation.
$${\displaystyle \eta(\lambda )=A+{\frac {B}{\lambda ^{2}}}}$$
From this, the book ...
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2
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What exactly is "dense" in Optical Density?
My book states that:
When passing from one medium to another, if light slows down, the second medium is said to be optically denser than the first medium, and if light speeds up, then the second ...
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What happens to the time period when refraction occurs? [duplicate]
I was studying light and had a doubt that when refraction occurs (rarer to denser just assuming) then frequency remains same but lambda (wavelength) and velocity decrease. But I cant quite figure out ...
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2
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862
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Translucent materials, like frosted glass, do have a refractive index?
I'm an architectural lighting designer in Mexico and I know the basics of absorption, transmission, reflection and refraction of materials. But I can't find anything about translucent materials like ...
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1
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What is the acceleration of light (photon) in vacuum? [duplicate]
We all know that the speed of light is 299792458m/s, but what is the acceleration of photons? That is to say, does the photon have a speed transition from zero to the speed of light?
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Why does the wave velocity of EM signals in a wire depend on the insulator's permittivity?
I'm in an electromagnetism class and struggling with a concept. The textbook derived several equations which state that the wave velocity of an electrical signal in a transmission line depends on the ...
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Direction of refraction of light confusion [duplicate]
Why exactly do light rays bend towards the normal as it travels from an optically rarer to denser medium, and similarly, why do they bend away from the normal as they move from optically denser to a ...
3
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1
answer
230
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How fast, based on the laws of physics can the Internet be? [closed]
Assuming the actual physics, optics, signal processing and similar, how fast can we increase the 'speed' of the Internet?
I know the limit would be $$v \le c,$$ but are there some other limits:
...
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Intuitive Explanation behind algebraically adding the vertical shifts produced by transparent objects
Given are two transparent slabs of different refractive indexes, a point object is placed at the bottom of $B$. My book says that the total shift produced is the algebraic sum of the shifts of each ...
user318780
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Why does light slow down in a medium? [duplicate]
I'm having difficulty understanding why light slows down in a medium. One explanation I found says the electric and magnetic fields in the light beam cause the electrons in the material to oscillate ...
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Do the light that we see from stars/galaxies travel at the speed of light? [duplicate]
From my understanding, the speed of light is reduced when traveling in a medium. Also, space is the closest thing we have to a vacuum, but it is not a perfect vacuum.
So I wonder if the almost vacuum ...
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Is the speed of light in is uniform non-vacuum medium constant for all observers? [duplicate]
I am running at $5 \text{ ms}^{-1}$ and holding a torch pointing in the direction of motion. This torch has a large block of glass attached to the end. Would a stationary observer see the light as ...
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1
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128
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Acceleration of Light when it moves through different medium
Assume three mediums with refractive index $a$ , $b$ , $c$ where is $a$ for Air and $b$ and $c$ are some different medium. Relation between them is $a<c<b$. As Light enters Via point $P$ and $Q$...
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How does change in Temperature affect Refractive Index/Optical Density of a medium?
In my school book its stated that:
With increase in temperature, the speed of light in a medium increases, so the refractive index of medium decreases.
I read in another answer that:
Refractive ...
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Is it possible to calculate speed of light in a mixture of A and B, by knowing the speed of light in both medium A and B seperately?
So we all know speed of light varies in different medium, which then makes me thinking is it possible for us to calculate the speed of light in a thoroughly mixed medium consists of X% of medium A and ...
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