As two notes approach perfect unison during tuning
PHYSICS · Single correct · A Level · Physics · Waves · Waves
Problem
As two notes approach perfect unison during tuning, the beat frequency heard by the musician decreases. Which of the following best explains this observation?
(a) The speed of sound in air decreases as the notes are tuned, so the wavelengths lengthen and the time between constructive interferences increases.
(b) The amplitudes of the two waves become smaller, so the interference envelope stretches out and the beats slow down.
(c) The frequency difference between the two notes becomes smaller, reducing the rate at which successive constructive interferences occur.
(d) Air preferentially damps rapid amplitude fluctuations, so high-frequency beats are absorbed more than low-frequency beats, leaving a slower beat pattern.