1. The problem statement, all variables and given/known data A 42.9cm long tube has a 42.9cm long insert that can be pulled in and out. A vibrating tuning fork is held next to the tube. As the insert is slowly pulled out, the sound from the tuning fork creates standing waves in the tube when the total length L is 46.8cm, 79.2cm, and 111.6cm. What is the frequency of the tuning fork? Take the speed of sound in air to be 343m/s 2. Relevant equations open-closed end (2n-1)/ 4 lamda = L 3. The attempt at a solution so I know this question has been posted before, but I dont really understand the solution. 79.2 - 46.8 = 32.4 cm or 0.324m Why do you need to multiply 0.324 by 2 to get the wavelength? Since it is open-closed, isn't it 1/4 lamda = L , which is times it by 4?