Problem

An organ uses standing sound waves in pipes of different lengths to produce different no...

An organ uses standing sound waves in pipes of different lengths to produce different notes. Your friend is an organist, and you play a trick on him by filling his organ pipes with helium gas. The speed of sound in helium is higher than the speed of sound in air by a factor of (See Table 13.1.) How will your prank affect the tones produced by the organ? (a) The notes will all go up in frequency by this factor. (b) The notes will all go down in frequency by this factor. (c) There will be no change. An experiment similar to this one is often performed at carnivals, when a performer fills his vocal tract with helium gas and then demonstrates his “new” voice. The pitch of the human voice is determined by the frequencies of standing waves in the vocal tract.