Jeanway 0 Posted April 20, 2004 ANYONE CARE TO EXPLAIN? Share this post Link to post Share on other sites
nik 0 Posted April 20, 2004 ANYONE CARE TO EXPLAIN? See the other thread on this topic. However: The speed of light can be determined from solving the Maxwell equations (in any medium). These equations result in a second order linear differential equation. The result of this equation in space is a sinusoidally varying waveform (in electric and magnetic fields). The "constant" of this equation is the product of the permeability and the dielectic constant of free space, which we call the speed of light. It's fascinating to think that we were able to determine the speed of light before we could measure it. Albert Einstein spent some time trying to find a way around Maxwell's equations for moving reference frames. His final conclusion was that these two constants mentioned above are constant in all reference frames, and thus the speed of light is constant in all reference frames. Pretty cool stuff. Some other fascinating results are solving Maxwells equations for various matterials: glass (not too hard), two different glass interfaces, metal, a plasma (why AM radio works well at night), and wave guides. We can get some neat results. Share this post Link to post Share on other sites
Ace 0 Posted April 20, 2004 I guess he gave the intelligent answer; I just say 186,000 miles per second... Share this post Link to post Share on other sites
Jeanway 0 Posted April 20, 2004 DON'T just leave us hanging here nik. Maxwell's Equations Please We aren't just a bunch of dolts in here, you know. We question everything, Sorry. Go on. Share this post Link to post Share on other sites
nik 0 Posted April 20, 2004 There are four differential equations developed about the turn of the 20th century to explain electromagnetic phenomena. They were named after C. Maxwell, though he wasn't the only one to bring the work to fruition. Many of these also are named for great scientists who made previously developed observations. I will explain these in words, since I don't have math fonts. Gauss's law: The "strength" of an electric field (penetrating a closed surface) is proportional to the charge contained within that surface. (Unnamed): There are no magnetic monopoles. Faraday's law: The induced electric field about a closed loop is proportional to the time rate of change in magnetic flux through that loop. Lenz's law, Magnetic analog to Faraday's law: The induced magntic field about a closed loop is proportional to the time rate of change of the electric flux through that loop and to the current through that loop. This is a general explanation for Maxwell's equations in space, but can take on additional terms for "sources" of magnetic and electric field. The last two can be used to derive the speed of light, which is an electromagnetic "disturbance." Share this post Link to post Share on other sites
Jeanway 0 Posted April 20, 2004 Fresnel certainly would have shot that all to crap? Share this post Link to post Share on other sites
nik 0 Posted April 20, 2004 Fresnel certainly would have shot that all to crap? Gosh dang, Jeanway! You know about Augustin Fresnel!? I know about two people who know about Fresnel....... Surprising, indeed! Share this post Link to post Share on other sites
Jeanway 0 Posted April 20, 2004 I love lighthouses nik Share this post Link to post Share on other sites
nik 0 Posted April 20, 2004 I love lighthouses nik And even fewer people who know that a lighthouse employs a Fresnel lens! Share this post Link to post Share on other sites
Jeanway 0 Posted April 20, 2004 It's all part of the job, nik Share this post Link to post Share on other sites
Xeroc 0 Posted April 22, 2004 Some additional info: Light as propagating electromagnetic waves: Note: This is a graph of field strength Link to Maxwell's equations Share this post Link to post Share on other sites
WEAREBORG4102 0 Posted April 22, 2004 anybody wiling to discuss balckbody radiation??? or the photoelectric effect??? Share this post Link to post Share on other sites
