First of all, thanks to everyone on the physics forum! My semester is almost over and I know I never would have gotten through it without the help of the people on these boards :)(adsbygoogle = window.adsbygoogle || []).push({});

Here's my question:

A certain pipe produces a fundmanetal frequency of 218 Hz in air. If the pipe is filled with helium at the same temperature, what fundamental frequency does it produce? The molar mass of air is 28.8 g/mol and the molar mass of helium is 4 g/mol.

I used v=lamda*f

344=lambda*218

lambda=1.578

Then, I assumed the wavelength (lambda) would be constant. From a table, I found the value of sound in helium to be 927 m/s. So 927=(1.578)f to get f=587.4593 Hz.

This is incorrect. Where did I go wrong? I'm not really what to make of the molar masses.

Thanks in advance,

eku_girl

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# Homework Help: Frequency in pipes

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