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Originally Posted by lyndonashmore
Why 6e6 per second? A second is a long time in the life of a e-m wave. Light has a frequency of about 6x10^14Hz. It takes 1.7x10^-15 secs for one oscillation. During this time the electron will have covered 10^-8 metre thermally.It is nothing.
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So, there is not enough time for the electron to interact with other electrons and lose energy.
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Originally Posted by lyndonashmore
Consider ac (and despite what others on this boeard say electrons do perform shm in ac currents. It is the basis (page 4?) of radio transmission. |
Why don't you cite a proper textbook about soild state physics, or metals?
Why do you have to rely on googling "SHM"?
Others on this board have
explained why electrons in a wire are not oscillating about a point.
But you come up with a reference to a 6-pages long document: at least you could cite
Feynman Lectures (but he probably does not say what you would like to hear).
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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.