First of all, I do not think that the speed of the sound in air matters, and I just used the formula Length= n*(wave length)/2, so L=3(3.47)/2 = about 5m. Now this is very unrealistic. So what do you think??If a third harmonic is generated on a guitar string, so that the sound produced in air has a wavelength of 3.47m, what is the length of the string? Assume the speed of waves on the guitar's string is 500 m/s and in air is 334m/s.
Thank you for your time.