Beats are produced by two waves given by ${y}_{1}=a\mathrm{sin}2000\text{\hspace{0.17em}}\pi t$ and ${y}_{2}=a\mathrm{sin}2008\text{\hspace{0.17em}}\pi t$. The number of beats heard per second is

(1) Zero

(2) One

(3) Four

(4) Eight

(3) Number of beats per second = n1 ~ n2

${\omega }_{1}=2000\pi =2\pi {n}_{1}$n1 = 1000

and ${\omega }_{2}=2008\pi =2\pi {n}_{2}$n2 = 1004

Number of beats heard per sec = 1004 – 1000 = 4

Difficulty Level:

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