Emf from radio broadcast

  • #1

Homework Statement


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.


Homework 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]

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.
 

Answers and Replies

  • #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.
 
  • #3
what equation would I use those in?
 
  • #4
Redbelly98
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Science Advisor
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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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