Plase, ? need help. ? need answer, formula and unit. PLEASE HURRY UP.. Two 270.0

Question

Plase, ? need help. ? need answer, formula and unit. PLEASE HURRY UP..

Two 270.0-W speakers, A and B, are separated by a distance D = 3.53 m. The speakers emit in-phase sound waves at a frequency f = 11700.0 Hz. Point Pi is located at Xi= 5.93 m and y = 0 m; point P2 is located at x2 = 5.93 m and Y2 = -delta y- Neglecting speaker B, what is the intensity, (in W/m2), of the sound at point Pi due to speaker A? Assume that the sound from the speaker is emitted uniformly in all directions. What is this intensity in terms of decibels (sound level, betaa1)? When both speakers are turned on, there is a maximum in their combined intensities at P*. As one moves toward P2, this intensity reaches a single minimum and then becomes maximized again at P2- How far is P2 from Pi, that is, what is Ay? You may assume that L >> y and that D >> y, which will allow you to simplify the algebra by using

Explanation / Answer

a) I (A1) = Power /(4*pi*r*r)

r= AP1 (line)

Intensity = 270/(4*3.14*(3.53*0.5*3.53*0.5+5.93*5.93) =0.561 W/m^2

b) Intensity in decibel =

=117.49 dB

c) For constructive interference,

AP2 - BP2 = WAVELENGTH = speed of sound/frequency = 343/11700 =0.0293

So delta y = 0.0293 m = 2.93cm

L=10*log I/Io =10log(0.561*10^12)

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