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Oct
22
comment Why don't electromagnetic waves require a medium?
Oh I disagree. Different phenomena are given different names for a reason. You wouldn't say this is the same as bremsstrahlung, would you? Granted, both result in the emission of radiation. The answer claims that the current produces motions "at just the right speeds". That makes it sound like there's some coherent motion giving off a particular frequency as in a radio antenna. Antennas can be understood classically; it takes quantum to derive Planck's law. This is an entirely different phenomenon, and the resulting spectrum is completely different. It's a bad analogy.
Oct
21
comment Why don't electromagnetic waves require a medium?
Looks like the author of this answer doesn't understand how a filament light bulb works...
Sep
15
comment Will current pass without any resistance?
Reread the last paragraph of my answer. Even with a "0 resistance wire", you still have internal resistance in your voltage source, which means that a finite amount of current flows. The electrons convert electrical potential energy at one end of the wire into kinetic energy at the other end.
Jun
18
revised Will current pass without any resistance?
added 117 characters in body
Jun
12
revised Is there a scientific term for the right-hand-(grip-)rule?
added 232 characters in body
Jun
12
answered Is there a scientific term for the right-hand-(grip-)rule?
Jun
11
comment What is the physics of traffic speed limit?
I'm voting to close this question as off-topic because this is a legal/social question, not physics.
Jun
11
awarded  Nice Answer
Jun
10
comment Is the Earth the center of the Solar System?
I agree that we can usually treat the barycenter of the Solar System as if it were inertial. But it's precisely that gradient of the potential that keeps us in the Milky Way. So we can't completely ignore such forces. I think it's important not to make blanket statements that might confuse the physics newbies, because they typically make it their job to find objections to such statements -- and rightly so. :)
Jun
10
revised Is the Earth the center of the Solar System?
added 741 characters in body
Jun
10
answered Is the Earth the center of the Solar System?
Jun
8
revised Is entanglement a classical phenomenon (last attempt)?
Correct singular form of phenomena
Jun
8
comment Thought experiment - would you notice if you fell into a black hole?
@shawnhcorey Coordinates can do basically anything you want them to do -- which is one of the main lessons of General Relativity. You really shouldn't downvote a good answer like this just because you don't understand what's going on. Feel free to ask questions, instead.
Jun
8
awarded  Guru
Jun
7
revised Can I simply reverse the indices in a contraction?
added 131 characters in body
Jun
7
comment Can I simply reverse the indices in a contraction?
That's true. I was going with Wald, who defines a covariant derivative to be torsion-free. But you're right that people do drop that condition for certain purposes. I'll add that caveat. Thanks!
Jun
7
revised Thought experiment - would you notice if you fell into a black hole?
added 198 characters in body
Jun
7
revised Thought experiment - would you notice if you fell into a black hole?
added 1876 characters in body
Jun
7
comment How many coils of a wire in an electromagnet would make 100 milliTeslas field?
In principle, yes, you can make the solenoid "walls" as thick as you want. Those formulas you see on the wikipedia page, for example, are for the magnetic field anywhere inside, and they don't say anything about the inner or outer radius of the wires. So you can wind over and over to increase the field strength. But the simpler formulas I used do assume an infinite length solenoid, so if the outer radius of your wires is comparable to the length of your solenoid, those formulas might not be so accurate.
Jun
6
awarded  Good Answer