Two loudspeakers, 4.0 m apart and facing each other, play identical sounds of the same frequency. You stand halfway between them, where there is a maximum of sound intensity. Moving from this point toward one of the speakers, you encounter your rst minimum of sound intensity when you have moved 0.25 m. You can assume the speed of sound in air is v = 340 m/s.

(a) What is the frequency of the sound? (b) If the frequency is then increased while you remain 0.25 m from the center, what is the rst frequency for which that location will be a maximum of sound intensity?

(c) Standing waves can occur when a wave is reected at a boundary, causing interference between the outgoing wave and its reection. This problem doesn't have a boundary, but we can still visualize the two notes being played as an outgoing wave and its reection. Solve the rst two parts of this problem using standing waves, or if you did that the rst time, solve them in an alternative way.