Figure P.9.5 shows an output pattern that was measured by a tiny microphone when two small piezo-loudspeakers separated by 15 cm were pointed toward the microphone at a distance of 1.5 m away. Given that the speed of sound at 20°C is 343 m/s, determine the approximate frequency at which the speakers were driven. Discuss the nature of the pattern and explain why it has a central minimum.

Fig P.9.5

Transcribed Image Text:

2.00 1.80 1.60 1.40 1.20 1.00 0.80 » 0.60 0.40 0.20 - 0.00 10 20 30 40 60 70 80 90 Position of Microphone (cm, zero-point arbitrary) Sound Intensity at Microphone (arbitrary units)