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The electric field part of an electromagnetic wave in vacuum is `E=3.1(N)/(C)cos[(1.8("rad")/("m"))y+(5.4xx10^(8)("rad")/(s))t]hati` The wavelength of this part of electromagnetic wave isA. 1.5mB. 2mC. 2.5mD. 3.5m |
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Answer» Correct Answer - D Given ` E = 3.1 N C^(-1)` `cos [( 1.8 rad m^(-1)) y + (5.4 xx 10^(8) rad s^(-1))t] hati " "….(i)` Comparing (i) with the equation `E= E_(0) cos (ky + omega t)" "…….(ii)` We get, ` k = 1.8 rad m^(-1)` `E_(0) 3.1 N C^(-1) , c = 3 xx 10^(8) ms^(-1) , omega = 5.4 xx 108 rad s^(-1)` Now ` lambda = (2pi)/(k) = ( 2 xx 22)/(1.8 xx 7) = 3.5m` |
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