Carey and Marcy are performing a lab to determine the speed of sound in air with the apparatus that was demonstrated in the video from the introduction. Marcy plays a 440 Hz tuning fork over the tube opening , while Carey slowly causes the water level in the tube to move downward from the zero mark. Carey hears the first amplification and makes a measurement of 19.4 cm. What kind of standing wave is being formed in the tube?

A. Fundamental, 1/4 of a wavelength

B. Fundamental, 1/2 of a wave length

C. Fundamental, 3/4 of a wavelength

D. 1st Overtone, 1 full wavelength

the frequency is the fundamental and distance is    L = ¼ λ

Explanation:

This problem is a phenomenon of resonance between the frequency of the tuning fork and the tube with one end open and the other end closed, in this case at the closed end you have a node and the open end a belly, so the wavelength is the basis is

          λ = 4 L

In this case L = 19.4 cm = 0.194 m

let's use the relationship between wave speed and wavelength frequency and

           v = λ f

where the frequency is f = 440 Hz

           v = 4 L f

let's calculate

           v = 4 0.194 440

           v = 341.44 m / s

so the frequency is the fundamental and distance is

                  L = ¼ λ

the answer is 46 mls because when you add the speed per second it increses the speed