Two loudspeakers are placed on a wall 2 m apart. A listener stands directly in front of one of the speakers, 81.7 m from the wall. The speakers are being driven by the same electric signal generated by a harmonic oscillator of frequency 4450 Hz. What is the phase difference ∆Φ between the two waves (generated by each speaker) when they reach the listener? The speed of the sound in air is 343 m/s. Answer in units of rad.

Respuesta :

Answer:

The phase difference is       [tex]\Delta \phi = 1.9995 rad[/tex]  

Explanation:

From the question we are told that

    The distance between the  loudspeakers is [tex]d = 2m[/tex]

     The distance of the listener from the wall  [tex]D = 81.7 \ m[/tex]

     The frequency of the  loudspeakers is  [tex]f = 4450Hz[/tex]

      The velocity of sound is [tex]v_s = 343 m/s[/tex]

     

The path difference of the sound wave that is getting to the listener is mathematically represented as

        [tex]\Delta z =\sqrt{d^2 + D^2} -D[/tex]

Substituting values

        [tex]\Delta z =\sqrt{2^2 + 81.7^2 } -81.7[/tex]

       [tex]\Delta z =0.0245m[/tex]

The phase difference is mathematically represented as

           [tex]\Delta \phi[/tex] =  [tex]\frac{2 \pi}{\lambda } * \Delta z[/tex]

Where [tex]\lambda[/tex] is the wavelength which is mathematically represented as

          [tex]\lambda = \frac{v_s }{f}[/tex]

substituting value  

          [tex]\lambda = \frac{343 }{4450}[/tex]

        [tex]\lambda = 0.0770 m[/tex]

Substituting value into the  equation for phase difference

      [tex]\Delta \phi[/tex] =  [tex]\frac{2 * 3.142 * 0.0245}{0.0770}[/tex]

      [tex]\Delta \phi = 1.9995 rad[/tex]  

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