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At 9:31 AM -0500 3/11/04, W. Hugh Chatfield I.S.P. wrote: >I got my degree in Physics in a class of 5 [up from the previous years class >of 0. The university had then massively overhauled the course in order to >attract students]. One experiment in particular was a classic one to >measure the ratio e/m for an electron. Nobody could get the "right answer" >with this apparatus. The prof assigned two teams to try to explain why. >The answer lay in the design of the apparatus. The filament was suspended >by two coils through which current passed... creating a magnetic field... >which was not negligible in the overall scheme of things. I remember that experiment. As I recall, the real problem was that the math was incredibly complicated, way beyond a freshman physics major, and that it relied on approximate solutions to equations involving elliptic integrals that could not be solved in closed form. The kicker was that the student lab devices we were using were way too small for the approximation to be valid. The coils used for the original, real experiments were much larger. All of which I only discovered after I was the only student in the class to get the "wrong" answer. :-) -- Elliotte Rusty Harold elharo@m... Effective XML (Addison-Wesley, 2003) http://www.cafeconleche.org/books/effectivexml http://www.amazon.com/exec/obidos/ISBN%3D0321150406/ref%3Dnosim/cafeaulaitA
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