Interference: Two in-phase loudspeakers that emit sound with the same frequency are placed along a wall and are separated by a distance of 8.00 m. A person is standing 12.0 m away from the wall, equidistant from the loudspeakers. When the person moves 3.00 m parallel to the wall, she experiences destructive interference for the second time. What is the frequency of the sound? The speed of sound in the room is 343 m/s. CAREFUL! The distance to the wall is NOT much greater than the distance between the speakers.
A) 278 Hz
B) 422 Hz
C) 452 Hz
D) 562 Hz
E) 694 Hz

Question

Quizplus · Accepted Answer

The distance between the two points of destructive interference is equal to half a wavelength. Therefore, the wavelength is 6.00 m. The frequency is then:f = v/λ = 343 m/s / 6.00 m = 57.2 Hz

Interference: Two In-Phase Loudspeakers That Emit Sound with the Same