A riverside warehouse has several small doors facing the river. Two of these doors are open as shown in the figure below. The walls of the warehouse are lined with sound-absorbing material. Two people stand at a distance L- 120 m from the wall with the open doors. Person A stands along a line passing through the midpoint between the open doors, and person B stands a distance y- 20 m to his side. A boat on the river sounds its horn. To person A, the sound is loud and clear. To person B, 1.70 m. Assuming person B is at the position of the first minimum, determine the distance d between the doors, center to center. sound is barely audible. The principal wavelength of the sound waves is m

In Young's experiment, the electric fields of the waves arriving at point P are given by E1 = (5.00 µN/C) sin{(4.74 × 1015)t} E2 = (9.00 µN/C) sin{(4.74 × 1015)t + 21.1 rad}, where time t is in seconds. What is the amplitude of the resultant electric field at point P?

The back wall of an auditorium is 26.0 m from the stage. If you are seated in the middle row, how much time elapses between a sound from the stage reaching your ear directly and the same sound reaching your ear after reflecting from the back wall?

Two loudspeakers are mounted on a rack, one h = 2.74 m above the other. Exactly 8.00 meters to the right of the midpoint, a microphone rests at point O. Point O is equally distant from each loudspeaker.   The loudspeakers are driven by the same tone generator and vibrate in phase at 390 Hz. It is possible to create a condition of destructive interference at Point O by changing one or both of the path lengths (r1 and r2) between speaker and microphone. Suppose that this is done by raising the upper speaker while leaving the lower speaker in place. What is the smallest vertical distance (in m) that you would need to raise the upper speaker by, in order to create destructive interference at Point O? (The speed of sound waves in air is 343 m/s.)