In aluminum the speed of sound is 5100 m/s. what is the wavelength of a sound wave of middle C at 264 Hz traveling through aluminum?

(a) The relationship between wavelength , frequency f and velocity v of a wave is

For the sound wave of our problem, the frequency is  while the velocity is , so its wavelength is 


(b) The only difference here is the velocity, because the speed of an electromagnetic wave is equal to the speed of light:

So, if we use the wavelength we found in the previous part, we get the frequency of the electromagnetic wave