Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Electromagnetic waves - antennas

  1. Jul 12, 2005 #1
    I just need a little direction to get started on this problem.


    A magnetic dipole is uded to detect an electromagnetic wave. The antenna is a coil of 50 turns with radius 5.0 cm. The EM wave has frequency 870 kHz, electric field amplitude 0.50 V/m, and magnetic field amplitude 1.7 x 10^-9 T.

    What is the amplitude of the induced emf in the coil?
     
  2. jcsd
  3. Jul 12, 2005 #2

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    I think you might need a review of the Faraday's electromagnetic induction law.

    Daniel.
     
  4. Jul 12, 2005 #3
    I will need a little more guidance than that. I am thinking that I need to find the emf, but I am not sure how I could do that with out a variable of time.

    Or would I just use the equation:

    [tex] \varepsilon_m = N \omega A B [/tex]
     
    Last edited: Jul 12, 2005
  5. Jul 12, 2005 #4

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    That's the right equation indeed and it follows really nicely, if you apply Faraday's law correctly and assume, for simplicity a cosinusoidal time dependence of the magnetic induction.

    Daniel.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook