All Questions
10
questions
1
vote
1
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149
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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 ...
0
votes
1
answer
174
views
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 ...
- 2,327
2
votes
1
answer
81
views
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?
- 181
2
votes
3
answers
669
views
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 ...
1
vote
2
answers
142
views
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 ...
- 1,087
0
votes
1
answer
76
views
Gain medium and the speed of light
I am currently studying optics, and when taking a closer look at refractive indices, I stumbled across gain mediums.
On Wikipedia it states that gain mediums can have a refractive index of $n<0$.
...
- 111
4
votes
3
answers
5k
views
How can the speed of light change in the medium when we know that it is always equal to $c$? [duplicate]
How can the speed of light change in the medium when we know that it is always equal to $c$? If we say the speed of light is changing in the medium, it will contradict the Einstein's law of special ...
2
votes
0
answers
286
views
Can time pass for a photon if it's moving in a medium? [duplicate]
If time does not pass for a photon traveling at the speed of light, which can only occur when traveling in a vacuum, what happens when it is slowed down by traveling through non vacuum space like ...
- 21
6
votes
2
answers
3k
views
Refractive index of dielectric in different frames of reference
The setup
A transparent isotropic dielectric medium moving in the negative $x'$ direction at speed $v$ in frame $S'$ is stationary in frame $S$, where it has refractive index $n$. In other words, ...
- 6,425
-7
votes
1
answer
1k
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Speed of light is not fixed? [closed]
In my research, I found that the speed of light is not fixed. IS it true?
Namely, We know that light refracts when the medium it travels through changes. Actually, light travels in the same medium ...
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