All Questions
Tagged with electromagnetic-radiation photons
163
questions
117
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9
answers
66k
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What is the relation between electromagnetic wave and photon?
At the end of this nice video (https://youtu.be/XiHVe8U5PhU?t=10m27s), she says that electromagnetic wave is a chain reaction of electric and magnetic fields creating each other so the chain of wave ...
- 1,681
209
votes
10
answers
270k
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If photons have no mass, how can they have momentum?
As an explanation of why a large gravitational field (such as a black hole) can bend light, I have heard that light has momentum. This is given as a solution to the problem of only massive objects ...
- 2,774
34
votes
4
answers
21k
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Explain reflection laws at the atomic level
The "equal angles" law of refection on a flat mirror is a macroscopic phenomenon. To put it in anthropomorphic terms, how do individual photons know the orientation of the mirror so as to bounce off ...
- 697
27
votes
4
answers
4k
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Is the electromagnetic spectrum discrete?
I'm just starting to learn physics and I have a question (that is probably stupid.)
I learned that energy levels that the bound electron can have are discrete. I also learned that when an electron ...
- 373
49
votes
8
answers
23k
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Amplitude of an electromagnetic wave containing a single photon
Given a light pulse in vacuum containing a single photon with an energy $E=h\nu$, what is the peak value of the electric / magnetic field?
- 1,056
55
votes
5
answers
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Scattering of light by light: experimental status
Scattering of light by light does not occur in the solutions of Maxwell's equations (since they are linear and EM waves obey superposition), but it is a prediction of QED (the most significant Feynman ...
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54
votes
5
answers
9k
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Are there any theoretical limits on the energy of a photon?
Is there any lower or upper limit on the energy of a photon? i.e. does the mathematical framework we currently use to study photons blow up when a photon surpasses a certain upper limit of energy? (or ...
- 7,319
18
votes
1
answer
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Relation between radio waves and photons generated by a classical current
Several questions have been posted on Physics SE regarding the relationship between photons and electromagnetic waves, and several good answers have been given. Some of those questions are listed ...
- 54.5k
7
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6
answers
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What exactly does the *frequency* of a photon mean?
If you emit a single photon, wait an interval, emit a second photon, wait the same interval, and keep repeating, is the resultant stream of photons describable by the frequency at which you emitted ...
- 173
29
votes
5
answers
35k
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What exactly is a quantum of light?
I am currently trying to learn some basic quantum mechanics and I am a bit confused. Wikipedia defines a photon as a quantum of light, which it further explains as some kind of a wave-packet.
What ...
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17
votes
5
answers
8k
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How many photons are needed to make a light wave?
What is the smallest number of photons needed to make a "light wave"?
In other words, how many (coherent?) photons start to exhibit classical behavior?
For example, how many photons are needed to get ...
- 3,254
12
votes
2
answers
2k
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Why doesn't there exist a wave function for a photon whereas it exists for an electron?
A photon is an excitation or a particle created in the electromagnetic field whereas an electron is an excitation or a particle created in the "electron" field, according to second-quantization.
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22
votes
5
answers
12k
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What exactly is meant by the wavelength of a photon?
I've been thinking about this for quite some time, and from looking online I haven't found a satisfying answer.
Lots of photons, such as visible-light photons have very small wavelength (which from ...
- 379
42
votes
7
answers
5k
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Do nuclei emit photons?
Generally in text books they say that when a electron goes from high energy state to a lower energy state it emits photons.
My question is, it is possible that a proton that goes from high energy ...
- 445
3
votes
3
answers
2k
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Frequency and wavelength of photons
I try to better understand how electromagnetic radiation works. So I have some questions.
If an antenna emits at 100MHz (the charges on the antenna oscillate at 100MHz) what frequency will have the ...
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