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Emf from radio broadcast

  1. Sep 7, 2009 #1
    1. The problem statement, all variables and given/known data
    An AM Radio station broadcasts isotropically(equally in all directions) with an average power of 4.00kW. A dipole receiving antenna 65.0cm long is at a location 4.00 mi from the transmitter. Compute the amplitude of the emf that is induced by this signal between the ends of the receiving antenna.


    2. Relevant equations
    [tex]P[/tex][tex]_{avg}[/tex]=S[tex]_{}avg[/tex]A
    E[tex]_{max}[/tex]=[tex]\sqrt{\mu_{\circ}[/tex]cP[tex]_{avg}[/tex]/2[tex]\pi[/tex]r^2}
    B[tex]_{max}[/tex]=[tex]\frac{E_{max}}{C}[/tex]

    3. The attempt at a solution
    Used the avg power to find the E[tex]_{max}[/tex] to be .0058V/M. tHen used this to find the B[tex]_{max}[/tex] to be 1.9305*10^-11T. I am not sure how to calculate the emf from this.
     
  2. jcsd
  3. Sep 7, 2009 #2

    Redbelly98

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    Use the fact that the antenna is 65.0 cm long, and the value of Emax that you found.
     
  4. Sep 7, 2009 #3
    what equation would I use those in?
     
  5. Sep 7, 2009 #4

    Redbelly98

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    Here's a hint: the units on Emax are V/m ... which could also be converted to V/cm if you like. You have the length in cm, as well as the number of Volts per cm ... so how many Volts?
     
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