Find the fundamental, first overtone and second overtone frequencies of an open organ pipe of length 20 cm. Speed of sound in air is `340 m s^-1`.

Answer

A, B, D

Explanation

`V=340m/s`
`I=20cmxx10^-2m`
Fundamental frequency
`=(V/21)=340/(2xx20xx10^-2)`
`=850 Hz`
We known first over tone
`((2V)/(2I))=(2xx340)/(2xx10xx10^-2) ` (for open pipe)`
`=1750Hz`
second overtone
`=3(V/2I)=3xx850=2500Hz`