Why are percentages of the change in f & wavelength much greater when sound waves are used instead of radio waves?
df/f=-v/c for a given relative velocity v between source & detector.
So, change in frequency is inversely proportional to speed of wave in the medium in which it propagates, c.
Since the velocity of sound is much smaller than velocity of electromagnetic radiation, for the same relative velocity, the freq and wavelength shifts are much greater for sound than for radio waves. esp since c is the same for both.