A wave travelling along positive x- axis is given by y = Asin (omega ,t - kx) . If it is reflected f

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14.Waves and Sound

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A wave travelling along positive $x-$ axis is given by $y = A\sin (\omega \,t - kx)$. If it is reflected from rigid boundary such that $80\%$ amplitude is reflected, then equation of reflected wave is

A

$y = A\sin (\omega \,t + kx)$

B

$y = - 0.8A\sin (\omega \,t + kx)$

C

$y = 0.8A\sin (\omega \,t + kx)$

D

$y = A\sin (\omega \,t + 0.8\,kx)$

Solution

(b) On getting reflected from a rigid boundary the wave suffers

Hence if ${y_{incident}}$= $A\sin (\omega t – kx)$

then ${y_{reflected}} = (0.8A)$ $\sin \left\{ {\omega t – k( – x) + \pi } \right\}$

$ = – 0.8A\sin (\omega t + kx)$ an additional phase change of $\pi $.

Standard 11

Physics

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