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Originally Posted by lyndonashmore
papageno wrote
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Why don't you cite a proper textbook about soild state physics, or metals?
Why do you have to rely on googling "SHM"?
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So that any one can follow the link - not everyone has access to a library, or wants to.
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Originally Posted by lyndonashmore
In ac the thermal motion of the electrons is at about 10^5 m/s. One cycle takes 0.02 s. During this time the electron will have travelled 2km thermally - and tet we still see our T/v sets.
Electrons are extremely mobile.
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Yes, but in a wire the electrons scatters on all sorts of things: what is the average scattering time (picoseconds, maybe?)?
High-Electron-Mobility-Transistors at low temperatures (1 K) have an average scattering time of 100s of picoseconds (10^-10 secs). In those 0.02 secs, an electron has scattered an average of 10^8 (100 milion) times.
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This makes it worse. In IG space the electrons do not make any collisions as they oscillate. If electrons in ac can do shm and collide all these times then there is no problem with my theory.
cheers,
lyndon |
(emphasis mine)
But that's exactly it: they don't! The individual electrons are zipping about all over the place. It is only when you take the collective behaviour of
many electrons, that you get your SHM.
Your model seems to think of electrons as cars on a busy motorway, all trying to keep an even safe distance from each other. One car briefly slows down beforing speeding back up, and you get a 'wave' of close-together cars travelling back down the line. If that car at the front repeatedly speeds up and slows down, you'd get a continous 'wave' going down the line. The mechanics are different, but the principal is
identical to what you are suggesting.
But that is incorrect. Its more like dodgems, everyone trying to maintain a safe distance but essentially driving in random directions (ok dodgems for scaredy cats, just bear with me
). Any one dodgem goes in a random direction, but looking from a distance you would still see waves, ebbs and flows of 'dodgem density'.