EK Beat Frequency

[deleted388502]

686. The beat frequency describes the change in
a. pitch
b. intensity
c. wavelength
d. velocity

EK says intensity. Why not pitch? isn't pitch directly correlated to frequency?

Thanks!

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[Czarcasm]

686. The beat frequency describes the change in
a. pitch
b. intensity
c. wavelength
d. velocity

EK says intensity. Why not pitch? isn't pitch directly correlated to frequency?

Thanks!

Two waves with different frequencies (pitch) maintain the same frequency as they're propagating through some point in space. If they collide into each other, they can either interfere with one another constructively or destructively, which alters the amplitude (or loudness) of the wave. Intensity is proportional to different characteristics including velocity, frequency squared, amplitude squared, and density of the medium. Because the only thing changing in this scenario is the amplitude of the waves and because this is directly proportional to intensity, choice B is the best answer. This image might help: http://www.phy.mtu.edu/~suits/beatgraph.gif