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Homework Help: Beat frequency of strobe lights

  1. Apr 7, 2009 #1
    1. The problem statement, all variables and given/known data
    The strobe lights on top of two tall radio towers both have a period of about 1.00 s. When turned on simultaneously, a keen observer notes that during an 813 s interval, the lights gradually fall out of synchronization and then come back into flashing synchronously. What is the interval ΔT between the periods of the two beacons?

    2. Relevant equations

    abs(frequency1-frequency2)=beat frequency

    3. The attempt at a solution
    it would appear that the two strobe lights have the same frequency, frequency=1/period=1 Hz...I dont know what to make of the 813 interval or what exactly delta-T refers to physically

    I know the beat frequency involves the superimposition of these two light waves...
  2. jcsd
  3. Apr 7, 2009 #2
    i have
    299,792,458 m/s=speed of light=frequency(wavelength)
    is this relevant?

    also is the frequency in this time interval 813 Hz? the period is 1 s i.e. the light completes an oscillation every second so in a 813 s time interval there 813 oscillations?

    i know that initially f1-f2=0
    then abs(f1-f2) doesn't = 0
    then it does again....
    however im not sure what delta-T refers to/asks for... and not sure how to work this
  4. Apr 7, 2009 #3
    nothing? help please!
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