All Questions
Tagged with refraction special-relativity
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Is the relativistic energy-momentum relation fundamental? [duplicate]
The following relativistic energy-momentum relationship is taken to be fundamental:
$$E^2=p^2c^2+m_0^2c^4.\tag{1}$$
Let us specialize to massless particles ($m_0=0$) so that we have:
$$E=p\ c.\tag{2}$$...
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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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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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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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1
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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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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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Mass density of photons in a refractive medium
The effective mass density of photons in a vacuum $\rho^{vac}_M$ is related to the photon energy density $\rho^{vac}_E$ by
$$\rho^{vac}_M=\frac{\rho^{vac}_E}{c^2}.$$
Is it true that the mass density ...
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Photon energy-momentum relation inside a material [duplicate]
I understand that the speed of light in a medium like glass, $c_n$, is reduced by the refractive index $n$ so that we have:
$$c_n=\frac{c}{n},$$
where $c$ is the speed of light in the vacuum.
Is it ...
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1
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Do quasiphotons have mass?
If I understand correctly, per special relativity, anything that travels at a speed of $c$ must be massless and conversely, anything massless must travel at precisely $c$ in akl reference frame. We ...
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What does light travel through or why it is independent of a medium? [duplicate]
According to my research and understanding I cant get over the fact that light needs no media to travel, or is it scientifically or mathematically proven?
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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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2
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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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59
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According to SR, massless objects must travel at the vacuum speed of light, yet light slows down in a medium. So why isn't light massive? [duplicate]
So I've already asked a similar question on Quora and the askphysics forum on Reddit, but haven't gotten many helpful answers. I did get one good answer that said that light SOMETIMES gains mass in ...
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Is the speed of light through a medium invariant, just like the speed of light through vacuum is invariant? Also, do time dilation etc. still occur?
So, we know the speed of light through a vacuum is $c$.
Let us say that both our observers are moving past each other at speed $v$ in a medium in which the speed of light is $c'$.
So, does the usual ...
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What do you 'see' if you are stationary relative to a photon in a refractive medium?
A particle with zero rest energy/mass must always be at $c$ in all referentials, even why, if you could get to its referential it would have zero total energy, effectively not existing in that ...
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Are longer days attributable to refraction or spacetime curvature?
There should be a perfect 12 hour day from sun rise to sun set at the equator, but there is actually about an extra 6 minutes. This is assumed to be due to refraction, but could it be spacetime ...
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Does $E^2=(mc^2)^2+(pc)^2$ hold for light travelling in an optically dense medium?
The rest mass of photon $m_0=0$ and photon travels at the speed of light in vacuum. So the energy of photon in vacuum is given by $$E_{vacuum}^2=(m_0c^2)^2+(pc)^2=(pc)^2$$ $$E_{vacuum}=pc=\gamma m_0c^...
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Can an object move faster than the speed of light in a medium? [duplicate]
In water the speed of light changes to $2.25 \cdot 10^8m/s$. Can a electron travel faster/travel at the same speed in water. I don't see any violation of SR. So shouldn't it be possible for an ...
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Is the speed of light universal for all mediums? [duplicate]
We know that the speed of light is constant in a vacuum and has the value c= 3× 10^8 m/s.
But in a medium such as glass(refractive index=1.5) the speed of light is 2× 10^8 m/s. Now considering the ...
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Is it possible to reduce the speed and frequency of a light wave to zero in a liquid medium?
Assume that two mirrors are located in a huge liquid medium – say, deep down on an ocean floor – with a refractive index of $n'$ as measured by an observer $A$ standing on the beach platform at rest ...
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Restoration of the speed of light [duplicate]
If you can slow down the speed of a photon, how does it speed back up to the speed of light once the slowing down is disabled?
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Refractive index of light upper bound?
Is there any upper bound for the refractive index of a theoretical material to occur? Would the relativistic effects be taken into consideration?
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Do all photons have the same proper time in different environment?
All photons have the same speed. In "space" (I mean when there is practically no matter) a photon will travel a distance faster than a photon in matter. But the speed is still the same.
Do 2 photons ...
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3
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Refraction and reflection in special relativity
I know that special relativity postulates that the speed of light is the same no matter the inertial reference system. Consider that we have a medium with absolute refractive index $n$ ( when the ...
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1
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733
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Bending a Laser Beam [closed]
We can bend a Laser beam by varying the refraction coefficient of the air.
We can bend a Laser beam by dispersing into the air small particles that have the same effect on the Laser Beam and small ...
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Help understanding the speed of light in media with refractive index < 1
I have read the standard explanations on this, but I still have trouble with convincing myself that information is not propagating at faster than the speed c in media of refractive index less then ...
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Lorentz invariance of Maxwell's equations in matter
I know that Maxwell's equations of electromagnetism are Lorentz invariant in a vacuum. But what about in a generalized medium, e.g. a metal, a rubber, a dielectric, a magnet? I have read it comes down ...
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Speed of light dependent on source velocity in other medium [duplicate]
Does speed of light depends upon the velocity of source in a medium (like water) other than space? if yes, does the speed gets added up when the light source moves in direction of light?
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What is Cherenkov radiation? [duplicate]
What is Cherenkov radiation? I came across this concept when I was learning SR.
Why can't particles moving at speed of excess of speed of light in the medium. Why it does not violate the limitation ...
user221098
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Rule of addition of velocities in water
Is the speed of light still the same for all inertial observers in water?
If not, what are the rules of addition of velocities in water according to special relativity?
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