Question

An air-filled pipe is found to have successive harmonics at 1120 hz , 1440 hz , and 1760 hz . it is unknown whether harmonics below 1120 hz and above 1760 hz exist in the pipe. what is the length of the pipe?

Answer 1

Fundamental frequency:
1/2 * (1440-1120) = 1/2(1760-1440) = 160 Hz

Wavelength = Speed/Fundamental frequency.
Note, speed of waves in air is approximate to 340 m/s

Wavelength = 340/160 = 2.125 m

Length of the pipe = 0.25*wavelength = 0.25*2.125 = 0.53125 m = 53.125 cm