Answer to Question #39600 in Acoustics for Jonathan

Question

In the wave equation, it states that wavelength = velocity of the wave ÷ frequency. Or is it the constant velocity of light 299,792,458 divided by the frequency. And if it is the velocity of the wave ÷ frequency, how do I find the velocity of the wave without knowing wavelength? All I know is frequency and the length of the string that is being plucked.

Answer 1

All oscillations (more explicitly standing waves) which can be excited in the string have wavelengths Lambda related to the string length L as

L = n * Lambda / 2

where n > 0 is arbitrary integer. Usually you need to calculate parameters of the lowest harmonic, so, you should take n = 1:

Lambda = 2*L.