You have a long pipe closed at one end and an electronic buzzer with which you can dial in different single frequency sounds.

Question

When you hold the buzzer near the end of the pipe, transmitting sound down the pipe, you determine that standing waves are established at frequencies of 150, 250, and 350 Hz. The frequency of 150 Hz is not necessarily the fundamental frequency. Determine the length of the pipe if the speed of sound in air is 343 m/s.

Answer 1

This is a closed pipe resonator which only contains the odd harmonics. Since the harmonics go 150, 250, 350 the fundamental must be 50 Hz. With a closed pipe resonator there is only a quarter wavelength within the pipe.

using 343= 50 Hx X wavelength we can calculate the wavelength and ten divide by 4 to find the length of the pipe