"A tuning fork with a frequency of 440 Hz is held above a resonance tube partially filled with water. Assuming that the speed of sound in air is 342 m/s, for what heights of the air column will resonances occur?"(adsbygoogle = window.adsbygoogle || []).push({});

f_{1}= 440 Hz

v = 342m/s

I'm not sure if this is refering to an open pipe, or a closed pipe.

For an open pipe,

f_{n}= (nv)/(2L) = nf_{1}

v/(2L) = f_{1}

L = v/(2f_{1})

L = 0.3886 m

But this is the length for the sound traveling up and down... i think. So the length is 0.194m. However, the answer gives 3 values, 0.194m, 0.583m, 0.972m. Even for a closed pipe, I there is only 1 value...

I must be doing something wrong. I don't think the speed of sound in water is a factor, because my first answer seems to be correct...

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# Homework Help: Resonance, find the lengths

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