Waves and Sounds

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Wave Speed: The Effects of Helium on the Human Voice


You may be familiar with the process in which helium causes the human voice to sound higher-pitched than usual. This occurs because sound waves propagate through the helium gas, which is lighter than ordinary air (composed mostly of nitrogen and oxygen).

Which of the following can you conclude based on this information?


Sound waves travel more slowly through helium than through ordinary air.


Sound waves travel more quickly through helium than through ordinary air.


The speed of sound is the same in helium as in the ‚Äčordinary air.


The speed of sound does not affect the pitch of your voice.