All Questions
Tagged with speed-of-light electromagnetic-radiation
173
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Is it possible to get an electromagnetic wave equation if the speed of light were infinite?
In an old question: How would night sky look like if the speed of light was infinite? the best answer was voted down to negative credits.
I cannot understand why. From Maxwell's equations, we derive ...
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What is the speed of light during reflection? [duplicate]
What is the speed of light in a vacuum when the light reflects off of a mirror?
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1
answer
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How is it possible that photons already move at the speed of light the moment they pop into existence? [duplicate]
This is a thought experiment and I might be horribly wrong. If we have an electron-positron annihilation a photon pops into existence. This photon is then supposedly moving at speed of light at the ...
3
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2
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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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Proof of speed of light from Maxwell's equations in integral form
Is it possible to prove that
$$\displaystyle c = \frac 1 {\sqrt{\epsilon_0 \mu_0}}$$
using Maxwell's equation in integral form?
Recently, I saw this kind of proof by Professor Walter Lewin in one of ...
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8
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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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1
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Velocity of de-Broglie Wave
I have been trying to figure out the solution to this problem of finding the "velocity" of de-Broglie's wave. I have tried to see answers from countless sources but none of them helped. My ...
0
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1
answer
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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 do i calculate change of momentum when I send a photon in the direction of travel
Say a spaceship is traveling at a certain velocity v (>>c) and it emits light from the nose of my spaceship in the direction of travel. The speed of light is finite and hence there should be a ...
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2
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Speed of light affected by gravity or frame dragging effect
If we do not really 100% know how light works as a oscillation we also do not know is its speed indeed constant no matter is there a space or space-time motion that can affect it. Could a device that ...
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6
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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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5
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Does electric field have a speed itself?
If we bring a charge into the system, it produces electric field around it. I wonder if the propagation of this electric field has the same speed as light. Note that I don't mean electromagnetic field....
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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 ...
0
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2
answers
96
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How photon travel diagonally in a spaceship at relativistic speed according to Special Relativity
According special relativity, the clock ticks slower on spaceship moving at relativistic speed because the light travels a longer diagonal distance with respect observer on ground.
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Why does redshift happen?
If an object B does NOT move away from us, doesn't matter whether it's 10 km or 5,000,000 km away from us, I think redshift wouldn't happen.
Now, if the object is moving away from us, it's said that ...
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