MCQ
Beats are produced by two waves given by $y_1 = a\,\, sin\,\,2000\,\, \pi t$ and $y_2 = a\,\, sin\,\, 2008\,\, \pi t$ . The number of beats heard per second is
- A$0$
- B$1$
- ✓$4$
- D$8$
✓
Answer
Correct option: C.
$4$
c
Number of beats per second $=\mathrm{n}_{1}=\mathrm{n}_{2}$
Number of beats per second $=\mathrm{n}_{1}=\mathrm{n}_{2}$
$\omega_{1}=2000 \pi=2 \pi n_{1} \Rightarrow n_{1}=1000$
$=\omega_{2}=2008 \pi=2 \pi \mathrm{n}_{2} \Rightarrow \mathrm{n}_{2}=1004$
Number of beats heard per sec
$=1004-1000=4$
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