A standing electromagnetic wave E=E_(m) cos kx. Cosomegat is sustained along the x axis in vacuum. Find the projection of the Poyntind vector on the x axis S_(x)(x,t) and the mean value of that projectionaveraged over an oscillation period.

A standing electromagnetic wave E=E_(m) cos kx. Cosomegat is sustained

1.	A standing electromagnetic wave E=E_(m) cos kx. Cosomegat is sustained along the x axis in vacuum. Find the projection of the Poyntind vector on the x axis S_(x)(x,t) and the mean value of that projectionaveraged over an oscillation period.
Answer» SOLUTION :`oversetrarr(E) = oversetrarr(E_(m)) cos KX omega t` `oversetrarr(H) = (oversetrarr(k) xx oversetrarr(E_(m)))/(mu_(0)omega) sin kx sin omegat` `oversetrarr(S) = oversetrarr(E) xx oversetrarr(H) = (oversetrarr(E_(m)) xx (oversetrarr(k)xx oversetrarr(E)_(m)))/(mu_(0)omega) (1)/(4) sin 2kx sin 2 omegat` Thus `S_(X) = (1)/(4) epsilon_(0) cE_(m)^(2) sin 2kx sin 2 omegat` (as `(1)/(mu_(0)c) = epsilon_(0)c)`

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A standing electromagnetic wave E=E_(m) cos kx. Cosomegat is sustained along the x axis in vacuum. Find the projection of the Poyntind vector on the x axis S_(x)(x,t) and the mean value of that projectionaveraged over an oscillation period.

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