Final answer:
A transition from a long wavelength to shorter wavelengths in a sound wave increases the frequency, which results in a higher pitch.
Step-by-step explanation:
When you observe a sound wave that transitions from a long wavelength to much shorter wavelengths, you are observing a change in the wave's frequency. According to the relationship between wavelength and frequency, known as the wave equation (velocity = frequency x wavelength), if the wavelength decreases while the speed of sound remains constant, the frequency must increase. Therefore, the correct answer is that the pitch of the sound increases. Higher frequency corresponds to a higher pitch. It is important to clarify some misconceptions: the amplitude of a wave is not directly affected by the frequency or wavelength; amplitude is related to the wave's energy. As a wave spreads out from the source, yes, the amplitude can decrease, but this is due to the energy being dispersed over a larger area, not directly due to a change in wavelength.