All Questions
Tagged with electromagnetic-radiation energy
164
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3
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171
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How to Measure Energy of a Electromagnetic Wave accounting also for frequency?
We know a way of measuring energy of a electromagnetic wave is the Poynting vector, which is independent of the frequency. But let's say we want to make two different electromagnetic waves, with ...
-1
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1
answer
69
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Interpretation of watts per square meter for intensity of radiation
The energy that an electromagnetic field can deliver to a system is proportional to the square of the field. However, we use the terminology watts per meter square to represent the amount of energy ...
- 3
2
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2
answers
207
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Does the formula $E = hf$ apply to all electromagnetic waves?
The formula $E=hf$ shows the energy contained in one photon. Here, we use the simple half wave dipole antenna to evaluate the energy of photons at different frequencies. Surprisingly that gives a ...
- 31
0
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2
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297
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Density function with Planck's law
I've been looking at all this for the last 2 days and I can't sleep anymore unless I understand it. I think I come to the below conclusion. Much appreciated.
Planck says that the below formula returns ...
- 200
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119
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Why is energy not conserved instantaneously in electromagnetic waves? [duplicate]
I don't know if its a valid question but it's been bugging me for a while so I'll ask it.
I know that the Poynting Vector $\vec{S}$ gives the intensity of the electromagnetic wave, and its related to ...
- 1,638
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101
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Is $∫ (1/2)εE^2 dV$ in the entire volume of rays propagation $= nhf$? [closed]
I asked it on ChatGPT but it gave kind of a mixed answer contradicting itself in the process several times here is some of it.
"Kushagra Singh:
~so you mean $∫ (1/2)εE^2 dV$ in the entire volume ...
- 19
3
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3
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Why don't we get infinite energy from a continous emission spectrum?
If the spectrum emitted contains all kinds of photons of all kinds of wavelengths, doesn't that mean it should have infinite number of photons of very small energies? For example, 4000 angstrom to ...
-1
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1
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112
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Why is the energy of a light wave not dependent on amplitude?
When searched up on Google, the formula for the energy of an electromagnetic wave is E = hv, wherein h is Planck's Constant, and v is it's frequency.
Why is amplitude not included in this equation? ...
- 480
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2
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62
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The energy density of E&M waves in intergalactic space
Let's imagine that we placed a cube with a side of 1 meter in the intergalactic space. How much energy in the form of electromagnetic waves will pass through a unit volume from all sources of ...
- 3
1
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16
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Does a standing wave on a path have different free energy than a traveling wave?
My somewhat naïve view is that the standing wave is "bound" to its path, and thus higher in free energy than a traveling wave of equivalent amplitude and wavelength. But I'm not sure how ...
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14
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8
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Why does high frequency have high energy?
The electromagnetic spectrum's wavelengths all travel at the same speed, $c$. Also, the wavelength $\lambda$ and frequency $\nu$ are related by $c = \lambda \cdot \nu$. Since all moving particles here ...
- 259
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Why is Wien's displacement law not discrete? [duplicate]
We are taught that the electrons emit electromagnetic waves/photons when transitioning from one quantum level to another in a discrete manner. This is what causes the spectral line of specific ...
- 43
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0
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47
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Radiation from a moving charge particle in expanding universe?
Moving charged particles generally emmit energy in form of radiation.
Assume a charged particle that is situated in a zone that can join the Hubble flow and therefore starts moving away from us.
As it ...
- 2,462
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1
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77
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How do we interpret $E=|\vec{p}|c$ in classical electromagnetism?
$$E=|\vec{p}|c$$
Can this relation be derived purely from electromagnetic theory?
I.e., is this a general statement about the EM field as whole and not just individual photons?
I.e.
$$\left(\frac{1}{2}...
- 6,636
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4
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114
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Absorption spectrum of white light of the Sun
When some photons in the white light from the sun are absorbed, this means some wavelengths will be missing, so how does that light still appear 'white', although some of its constituents are missing?
