InterviewSolution
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InterviewSolution
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The electric field in an electromahetic wave is given by `E = 100sin omega (t-x//c)`. Find the energy contained in a cylinder of crross section `20cm^(2)` and length `1 m` along the `x`-axis. Also find intensity of wave. |
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Answer» The energy density `u_(av) = (1)/(2)in_(0)E_(0)^(2)` The volume of cylinder `V = Al` The enegry contained in this volume `U = u_(av) V = (1)/(2)in_(0)E_(0)^(2)Al` `= (1)/(2)(8.85 xx 10^(-12)) (100)^(2)(20 xx 10^(-4))(1)` `= 8.85 xx 10^(-11) J` The intensity of wave is `I = (1)/(2)in_(0)E_(0)^(2)c` `= (1)/(2)(8.85 xx 10^(-12))(100)^(2)(3xx 10^(8))` `= 13.3 W//m^(2)` |
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