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

question 7

Multiple Choice

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