MCQ
Beats are produced by two waves ${y_1} = a\sin 1000\,\pi t,$ ${y_2} = a\sin 998\pi t$The number of beats heard/sec is
  • A
    $0$
  • B
    $2$
  • $1$
  • D
    $4$

Answer

Correct option: C.
$1$
c
(c) ${n_1} = \frac{{1000\pi }}{{2\pi }} = 500Hz$ and ${n_2} = \frac{{998\pi }}{{2\pi }} = 499\,Hz$
Hence beat frequency = ${n_1} - {n_2} = 1$

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