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Waves II. Interference.

  1. Mar 8, 2009 #1
    1. The problem statement, all variables and given/known data

    Two speakers are mounted on a wall in an auditorium. One is at floor level and the other is 3 m directly above the first. The speakers emit sound waves in phase at a frequency of 686 Hz. A line is drawn on the floor, perpendicular to the wall beginning at the lower speaker and extending out into the room.
    a. What is the greatest distance from the lower speaker along this line where there will be a minimum in the sound intesity?
    b. How many minimas altogether will there be along this line? Explain.

    2. Relevant equations

    Change in L = |L2- L1|

    Change in L / wavelength = .5, 1.5, 2.5 ...

    for fully destructive interference.
    3. The attempt at a solution

    change in L = 3

    and I must find L1.

    f= 686 Hz
  2. jcsd
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