Calculating Induced EMF from AM Radio Broadcast and Dipole Antenna

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Homework Help Overview

The problem involves calculating the induced electromotive force (emf) in a dipole antenna due to an AM radio broadcast. The context includes parameters such as the average power of the broadcast, the distance from the transmitter, and the length of the antenna.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to calculate the maximum electric field (Emax) and magnetic field (Bmax) using the average power of the radio station. They express uncertainty about how to derive the emf from these values. Other participants suggest using the length of the antenna and the calculated Emax to find the induced emf.

Discussion Status

Participants are actively engaging with the problem, offering hints and guidance on how to relate the electric field to the length of the antenna. There is a focus on clarifying the relationship between the units and the quantities involved, but no consensus has been reached on the specific equation to use for calculating the emf.

Contextual Notes

The discussion includes a focus on unit conversion and the relationship between electric field strength and antenna length, indicating a potential gap in the original poster's understanding of how to apply these concepts in the context of the problem.

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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


P_{avg}=S_{}avgA
E_{max}=\sqrt{\mu_{\circ}cP_{avg}/2\pir^2}
B_{max}=\frac{E_{max}}{C}

The Attempt at a Solution


Used the avg power to find the E_{max} to be .0058V/M. tHen used this to find the B_{max} to be 1.9305*10^-11T. I am not sure how to calculate the emf from this.
 
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Use the fact that the antenna is 65.0 cm long, and the value of Emax that you found.
 
what equation would I use those in?
 
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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