Question

person standing on a railway platform notices that the sound of an approaching train's whistle changes in pitch (frequency) train passes by. This phenomenon is best explained by:

• A. Refraction of sound
• B. Diffraction of sound
• C. Doppler effect
• D. Resonance

Answer 1

Answer:

C. Doppler effect

Definition: The Doppler effect is the change in the observed frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source.