Two loudspeakers, A and B, are driven by the same amplifier and emit sinusoidal waves in phase. Speaker B is 12.0 m to the right of speaker A. The frequency of the waves emitted by each speaker is 688 Hz. You are standing between the speakers, along the line connecting them, and are at a point of constructive interference. How far must you walk toward speaker B to move to a point of destructive interference?

A speaker is producing spherically symmetric sounds with a total power of 88.5 W. If the speaker is located at the centre of a sphere with a radius of 2.20 m, what is the power received on a 1.70 m by 1.50 m area on the sphere? Give your answer in Watts to 2 decimal places.

Two loudspeakers on a concert stage are vibrating in phase. A listener is 52.5 m from the left speaker and 24.0 m from the right one. The listener can respond to all frequencies from 20 to 20 000 Hz, and the speed of sound is 343 m/s. What are the two lowest frequencies that can be heard loudly due to constructive interference?

For testing purposes, a musical instrument manufacturing company creates a device so that when you blow into one end with your instrument, sound comes out the other end in opposite directions. A sound technician uses a whistle and generates sound waves with a frequency of 242 Hz. The waves travel in opposite directions in a band room, are reflected by end walls, and return. The band room is 44.0 m long and the whistle is located 14.0 m from one end. What is the phase difference (in degrees) between the reflected waves when they meet at the source of the sound? The speed of sound in air is 343 m/s.