In the figure, two speakers separated by distance d1 = 2.40 m are in phase. You

Question

In the figure, two speakers separated by distance d1 = 2.40 m are in phase. You are standing 4.40 m directly in front of one speaker. Each speaker has an output power of 1.40 W. Because the speakers are at different distances, there will be frequencies at which the sound from the speakers interferes destructively. But because the speakers are at different distances, the sound intensities will not be the same, so the destructive interference will not be complete. We want to find the sound level when there is destructive interference. Use 343 m/s for the speed of sound in air. (a) What is the lowest frequency that gives minimum signal (destructive interference) at your ear? (b) What is the second lowest frequency that gives minimum signal? (c) What is the intensity from the near speaker? (d) What is the sound level from the near speaker? (e) What is the intensity from the far speaker? (f) What is the combined intensity during destructive interference? Because the sources are coherent, amplitudes add but intensities do not. (g) What is the sound level during destructive interference?

Explanation / Answer

DH Best Answer - Chosen by Voters a) the difference in distance to the listener is sqrt(3.10^2 + 2.30^2) - 3.1 = 0.76m b) minimum destructive interference occurs when d = ?/2 so ? = 2*d = 2*0.76 = 1.52m so f = c/? = 343/1.52 = 226Hz c) the next frequency is d = 3?/2 so ? = 2*d/3 = 2*0.76/3 = 0.5067m so f = c/? = 343/0.5067 = 677Hz d) constructive interference occurs at d = ? = 0.76m f = c/? = 343/0.76 = 451Hz

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.