Question

1. A howler monkey is the loudest land animal and, under some circumstances, can be heard up to a distance of 6.78 km. Assume the acoustic output of a howler to be uniform in all directions and that the threshold of hearing is 1.0 × 10^12 W/m2. The acoustic power, in mW, emitted by the howler is closest to

2. The sound from a single source can reach point O by two different paths. One path is 19.9 m long and the second path is 22.7 m long. The sound destructively interferes at point O. What is the minimum frequency of the source if the speed of sound is 340 m/s?

3. Two stereo speakers mounted 4.3 m apart on a wall emit identical in-phase sound waves. You are standing at the opposite wall of the room at a point directly between the two speakers. You walk 1.4 m parallel to the wall, to a location where you first notice that the sound intensity drops to zero. If the wall along which you are walking is 10.7 m from the wall with the speakers, what is the wavelength of the sound waves? CAREFUL! The distance to the wall is NOT much greater than the distance between the speakers.

Answer 1