Two in-phase loudspeakers are placed along a wall and are separated by a distance of 4.00 m. They emit sound with a frequency of 514 Hz. A person is standing away from the wall, in front of one of the loudspeakers. What is the closest distance from the wall the person can stand and hear constructive interference? The speed of sound in air is 343 m/s.
A) 0.344 m
B) 0.729 m
C) 1.15 m
D) 1.64 m

Question

Quizplus · Accepted Answer

Constructive interference occurs when the path difference is a multiple of the wavelength. The wavelength is calculated as speed/frequency = 343 m/s / 514 Hz = 0.667 m. The closest distance for constructive interference is when the path difference is half the wavelength, which is 0.667 m / 2 = 0.334 m. Considering the geometry, the closest distance from the wall is approximately 0.729 m.

Two In-Phase Loudspeakers Are Placed Along a Wall and Are