Q. Three sound waves of equal amplitudes have frequencies (n - 1), n, (n + 1). They superimpose to give beats. The number of beats produced per second will be
A) 1
B) 4
C) 3
D) 2
Explanation
[Solution] The resultant amplitude varies as $(1 + 2\cos 2\pi t)$, which peaks twice per second: 2 beats/s. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.