velocity is given by: velocity=wavelength×frequency We note that the wavelength of a wave is twice the length of the string (2w) in the first harmonic. velocity=329 m/s wavelength=2w frequency=392 substituting the values in our equation we get: 329=2w(392) 329=784w solving for w we get w=329/784 w= 0.41964~0.42 m