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The electric field in an electromagnetic wave is given by `E=( 50N (C^-1)) sin omega (t-x/c).` Find the energy contained in a cylinder of cross section `10 cm^2` and length 50 cm along the x- axis. |
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Answer» Correct Answer - A::B `u_E = u_B = 1/2 epsilon_0 E^2` `= 1/2 epsilon_0 ((E_0)/(sqrt 2))^2` `=1/4 epsilon _0 E_0^2` `= 1/4 (8.86 xx 10^-12)(50)^2` `=5.54 xx 10^-9 J//m^3` Total energy = `(u_E + u_B)` (Given volume) `= 2 xx 5.54 xx 10^-9 xx (10 xx 10^-4)(0.50)` = `5.55 xx 10^-12 J`. |
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