You are standing at the midpoint between two speakers, a distance D away from each. The speakers are playing the exact same sound of frequency 170 Hz in phase with each other. Describe what happens when you walk 1.5 m directly toward one of the speakers. Assume the speed of sound is 340 m/s. Also assume you can't hear any sounds except those produced by the speakers.

Question

Group of answer choices :

You begin by hearing nothing, but the sound gets louder. Then it gets quieter again until you can't hear it anymore.

You begin by hearing nothing, but the sound gets louder. Then it gets quieter again until you can't hear it anymore. Then it gets louder again.

You begin by hearing a loud sound that gets quieter until you can't hear it anymore. Then it gets louder again until it is as loud as where you started. Then it gets quieter again until you can't hear it anymore.

You begin by hearing nothing, but the sound gets louder.

You begin by hearing a loud sound that gets quieter until you can't hear it anymore. Then it gets louder again until it is as loud as where you started.

You begin by hearing a loud sound that gets quieter until you can't hear it anymore.

Answer 1

https://en.wikipedia.org/wiki/Standing_wave
In the middle they are in phase and you hear loud.
period = 1/170 s
wavelength = 340 m/s* (1/170 s) = 2 meters
so we move 3/4 of a wavelength.
The standing wave is of form
2 A cos 2 pi x/L * cos wt
note used cos to make max at x = 0 in middle
if x/L = 3/4
we have
2 A cos 6 pi /4* cos wt
= 2 A cos 3pi /2 * cos wt
well cos 3 pi/2 = ZERO!!!, silent there and every quarter wavelength thereafter until you hit the far wall

Answer 2

I mean every half wavelength until you hit the wall.