All Questions
Tagged with electromagnetic-radiation quantum-mechanics
83
questions
49
votes
8
answers
23k
views
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
8
votes
4
answers
1k
views
How can things around us have different colours if they have specific emission spectra?
Objects appear in different colours because they absorb some colours (wavelengths) and reflect or transmit other colours. The colours we see are the wavelengths that are reflected or transmitted.
As ...
- 1,064
18
votes
1
answer
2k
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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
156
votes
1
answer
15k
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What is an "attosecond pulse", and what can you use it for?
The 2023 Nobel Prize in Physics was announced today, and it was awarded to Pierre Agostini, Ferenc Krausz and Anne L’Huillier, for
“experimental methods that generate attosecond pulses of light for ...
- 134k
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 ...
- 495
10
votes
2
answers
3k
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How exactly does applying the Equipartition Theorem to radiation leads to UV catastrophe?
I'm reading a book by George Gamow, "Thirty years that shook Physics" and have trouble understanding his way of describing the UV catastrophe. In a first part he points out that applying the ...
- 279
6
votes
4
answers
6k
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Bohr's model of an atom doesn't seem to have overcome the drawback of Rutherford's model
We, as high school students have been taught that-because Bohr's model of an atom assigns specific orbits for electrons-that it is better than Rutherford's model. But what Rutherford failed to explain ...
- 61
2
votes
2
answers
9k
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Why electrons can't radiate in their atoms' orbits?
It's an old-new question (I found only one similar question with unsatisfactory (for me) answer: Where did Schrödinger solve the radiating problem of Bohr's model?)
It's strange for me how all books ...
- 2,071
9
votes
2
answers
8k
views
What IS reflection?
How does quantum electrodynamics actually explain HOW reflection occurs on a microscopic scale?
Note that Feynman's QED lecture series/book is not sufficient, as he only assumes that light DOES ...
- 1,550
3
votes
3
answers
2k
views
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 ...
- 337
7
votes
5
answers
11k
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Interesting relationship between diffraction and Heisenberg’s uncertainty principle?
I recently came across an interesting explanation of diffraction through an aperture which does not use Huygens’ construction but instead relies on Heisenberg’s uncertainty principle:
The uncertainty ...
- 1,546
5
votes
3
answers
10k
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How does light oscillate?
Why do we say that electromagnetic wave is oscillating? Or does light propagate really in a wavy form like this image?
What is making the photons oscillate and how is it oscillating is it oscillating ...
- 1,925
4
votes
1
answer
220
views
Planck's catastrophe?
In deriving Planck's blackbody formula, the number density of normal modes (per unit frequency$^\dagger$) is found, given by
$$
N(\omega)=\frac{V}{\pi^2c^3}\omega^2,
$$
where $V$ is the volume of the ...
- 1,951
10
votes
5
answers
6k
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Why does an accelerated charge radiate away energy?
My textbook says:
"Neils Bohr objected to the idea of an electron orbiting a nucleus in a circular orbit. An electron experiences centripetal acceleration and an accelerated charge radiates away ...
- 797
7
votes
6
answers
3k
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Do photons take all paths or not? [closed]
There are a lot of questions about this topic on this site, none of them answer my question specifically.
I have read this question:
What does a photon emitted by an atom "look" like?
I ...
- 29k