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 air is 343 m/s.
A)278 Hz
B)422 Hz
C)452 Hz
D)562 Hz
E)694 Hz

Question

Quizplus · Accepted Answer

The distance between the first and second destructive interference is 6.00 m. This corresponds to 3 wavelengths, so the wavelength is 2.00 m. The frequency is then:f = v/λ = 343 m/s / 2.00 m = 171.5 Hz

Two In-Phase Loudspeakers That Emit Sound with the Same Frequency