Kaplan Nursing Entrance Exam Practice 2025 – Comprehensive Prep

The Doppler effect specifically describes how the frequency and wavelength of a wave change in relation to an observer moving relative to the source of the waves. When an object emitting waves (such as sound or light) moves closer to an observer, the waves compress, leading to a shorter wavelength and an increase in frequency. This is perceived as a higher pitch in sound or a shift toward the blue end of the spectrum in light. Conversely, as the object moves away from the observer, the waves stretch, resulting in a longer wavelength and a decrease in frequency, perceived as a lower pitch in sound or a shift toward the red end of the spectrum in light.

This phenomenon is crucial in various fields, such as astronomy, where it allows scientists to determine the movement of stars and galaxies based on the light they emit. The other options do not correctly capture the essence of the Doppler effect—one discusses the constant speed of light, another addresses interactions of sound in different mediums, and the last refers to radio waves, which while related, do not encompass the full phenomenon of the Doppler effect.