Use this for questions relating to the proper use of physics terminology or nomenclature.
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2answers
155 views
What postulate means in physics?
What does postulate mean in physics? What is their role in physical theories?
Is it possible to break physical postulates?
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1answer
53 views
Conversion of ideal gas to real gas via $Z$ compression factor
The ideal gas equation $PV=nRT$ can be converted into real gas equation by compression factor $Z$ i.e $PV=Z~ nRT)$. My question is what is $Z$ and how does it arise? Is $PV/nRT$ a compression ratio of ...
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0answers
159 views
Physical interpretation: weighted eigenvalues of the Laplacian with a potential
I'm a mathematician with only the basic knowledge of Physics, so my question may be trivial: in this case, mercy me. :-)
Let $\Omega \subseteq \mathbb{R}^N$ be a domain and let $V,m:\Omega \to ...
3
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0answers
103 views
Meaning of spin
I'm pretty astounded that I did not hear about this sooner, but in my course on QFT our professor told us that the concept of spin can be used to mean three things:
Mechanical spin (apparently a ...
2
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0answers
279 views
de Sitter and anti de Sitter metric
Is the following correct for the distance $d$ from the origin $(0,0)$ to point $(t,x)$ in the 2-dimensional
de-Sitter and anti de-Sitter spaces? Here, $t$ is time and the distance may be called the ...
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0answers
45 views
Trying to speak correctly of spacetime intervals and how to compare them
Is it correct to speak of "magnitude of a spacetime interval"?
For instance, considering a pair of (distinct) events, $A$ and $B$, which are lightlike separated, is it correct to say that "the ...
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0answers
41 views
What name would you give to the method of approximating an arbitrary magnet with many smaller dipoles?
Let's say I had an arbitrarily shaped permanent magnet, with total magnetic moment $M_{0}$. Ways to calculate the magnetic field of this magnet include an analytic solution (if one exists), as well ...
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0answers
197 views
What is the relationship between Luminosity, Intensity, and Flux?
I am always confused by the terminology:
In high energy particle scattering, and in particular, in the context of collider physics, what is the relationship between luminosity, intensity and flux? ...
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0answers
72 views
Is putting a charged balloon up to a neutral wall polarization AND temporary induction, or just polarization?
Is putting a balloon that is charged up against a wall and having it stick polarization AND charging by temporary induction, or just polarization?
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0answers
265 views
What is a boundary condition for capacitors/dielectrics?
I am extremely confused about what boundary conditions are. One minute ago I was solving easy capacitor questions and the next minute I am being asked boundary condition questions and there is no such ...
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0answers
55 views
Magnitude of a photon?
I encountered the following sentence in my textbook, which I don't quite understand, and after an unfruitful google search, I still can't figure out what they mean by magnitude in this context:
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0answers
43 views
What is to be considered a “body” in physics?
Well, the question says it all; is there a definition of body in physics? What is to be considered a physical object and what it cannot?
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0answers
194 views
How is the term “Born level” usually defined?
How is the term "Born level" usually defined, e.g. in talking about the $pp\to Z/\gamma^*\to e^+e^-$ cross section at Born level?
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0answers
218 views
What is the correct definition of “group velocity dispersion”?
When we talk about a medium with dispersion, we can define the phase velocity $v_\phi = \omega/k$ and the group velocity $v_g = d\omega/dk$. Likewise the phase index $n = c/v_\phi$ and the group index ...
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0answers
33 views
Term for “atmospheric ricochet” due to wrong “angle-of-attack”
I watched "Apollo 13" yesterday, and they had the "angle-of-attack" problem that had to be manually solved, to prevent the ship from "ricochet[ing] off the atmosphere like a rock skipping off a pond".
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0answers
195 views
Is Photosynthetic Photon Flux Density (PPFD) a synonym for Photosynthetically Active Radiation (PAR)?
Both have units of $\mu\text{mol m}^{-2}\text{s}^{-1}$ and refer to light in the 400-700 nm range - that activates photosynthesis. However, I just want to confirm that these are synonyms and don't ...
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0answers
112 views
What is the electric field part of an EM wave? Radiation field or the induction field?
Look at this image:
I wonder if the electric field is from the induction field from a vibrating electron or the radiation field? If it is from the radiation field, as I suppose, than can someone ...
