You are standing 7 feet from one speaker and 13 feet from another. Both speakers are producing the same sound. If the combined sound from both speakers is especially loud at your location, which of the following could be the wavelength of the sound? Choose all that apply.

1 foot
2 feet
3 feet
4 feet
5 feet
6 feet
7 feet
8 feet
9 feet
10 feet
12 feet
18 feet

And how do you find this out>?

2 answers

A wavelength of 1, 2 or 3 feet will allow there to be constructive interference at the two locations. That corresponds to 6, 3 or 2 wavelengths difference between the two locations.
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