MCQ
Two waves of frequencies $20 Hz$ and $30 Hz.$ Travels out from a common point. The phase difference between them after $0.6 sec$ is
  • Zero
  • B
    $\frac{\pi }{2}$
  • C
    $\pi $
  • D
    $\frac{{3\pi }}{4}$

Answer

Correct option: A.
Zero
a
(a) Beats period = $\frac{1}{{30 - 20}} = 0.1  sec$
$\Delta \phi = \frac{{2\pi }}{T}\Delta .t = \frac{{2\pi }}{{0.1}} \times 0.6 = 2\pi \times 6 = 12 \pi $ or Zero.

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