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Electromagnetic waves [simple one]

  1. Mar 16, 2009 #1
    1. The problem statement, all variables and given/known data

    Public television station KQED in San Francisco broadcasts a sinusoidal radio signal at a power of 316 kW. Assume that the wave spreads out uniformly into a hemisphere above the ground.

    At a home 6.00 km away from the antenna, what is the average density of the energy this wave carries?

    For the energy density in part (a), what percentage is due to the electric field?

    For the energy density in part (a), what percentage is due to the magnetic field?

    2. Relevant equations

    u= P/ (c*a)

    u=1/2*epsilon* E^2 + 1/2mu * B^2

    3. The attempt at a solution
    i managed to do part A, by using equation u=P/(c*a)

    i dont know how to get the percentage,, please advise
  2. jcsd
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