Question

An air-filled pipe is found to have successive harmonics at 630 Hz , 810 Hz , and 990 Hz . It is unknown whether harmonics below 630 Hz and above 990 Hz exist in the pipe. What is the length of the pipe?What type of pipe do you have?

Answer 1

Answer:

0.95277 m

one end closed and the other end open

Explanation:

The harmonics are

630, 810, 990

So,

$7\times 90=630,\ 9\times 90=810,\ 11\times 90=990$

This can be only done when the pipe has one end open and the other end closed.

The fundamental frequency is 90 Hz

Fundamental frequency is given by

$f=\dfrac{v}{4L}\\\Rightarrow L=\dfrac{v}{4f}\\\Rightarrow L=\dfrac{343}{4\times 90}\\\Rightarrow L=0.95278\ m$

The length of the pipe is 0.95277 m

The pipe has one end closed and the other end open