Question

Go back to the Sound Simulation once again. The one we used before, called Sound, found at phet.colorado.edu/en/simulation/sound . This time, click on the "two source interference" tab, and play around. Try different frequencies. You can drag the listener up and down the screen now, as well as in and out. Move the head around and listen to what the "person" hears. (It's important that you listen after you've stopped dragging: the motion when you're dragging has a subtle effect on what you hear that we're not going into just yet.) After playing for a bit, come back here and select the statements which are true (leave the false statements unchecked)."

A: "As you move the listener to different points, there is more than one physical location where constructive interference occurs (loud spots)."

B: You can only get constructive and destructive interference if waves are longitudinal (transverse waves don't exhibit interference in the same way).

C: "If the distance from listener to speakers is different by exactly half of a wavelength, the sound cancels out at this point (destructive interference)."

D: The distance you need to move the listener to get from one interference minimum to the next (one quiet spot to the next) is smaller if the frequency of the sound is higher.

E: "If the distance from listener to speakers is different by exactly one full wavelength, the sound cancels out at this point (destructive interference)."

Answer 1

Correct options are

(A) "As you move the listener to different points, there is more than one physical location where constructive interference occurs (loud spots)."

(C) "If the distance from listener to speakers is different by exactly half of a wavelength, the sound cancels out at this point (destructive interference)."

(D) The distance you need to move the listener to get from one interference minimum to the next (one quiet spot to the next) is smaller if the frequency of the sound is higher.