CBSE Class 11-science Answered

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Asked by sherry.sharma771 | 08 Feb, 2023, 08:25: AM

Expert Answer

Let a sound wave is represented by y = A sin ( k x ± ω t ) .............................(1)

positive sign is wave going towards right and -ve sign is wave going towards left.

Corresponding pressure wave to the sound wave given in eqn.(1) is

begin mathsize 14px style capital delta P space equals space minus capital delta P subscript m a x end subscript space cos space left parenthesis k space x space plus-or-minus space omega space t space right parenthesis end style

....................................... (2)

At t = 0 , equation of snapshot for displacement of particle is , y = A sin ( k x ) ............................(3)

At t = 0 , equation of snapshot for pressure wave is ,

begin mathsize 14px style capital delta P space equals space minus capital delta P subscript m a x end subscript space cos space left parenthesis k space x space right parenthesis end style

...........................(4)

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Let us analyse option (A)

(A) for wave travelling left or right , graph-(i) is correct

Above statement is false From eqn.(3) , we get sine wave graph at t = 0 whether the wave is going towards left or right.

Hence , from eqn.(4) corresponding pressure wave is negative cosine wave.

Whereas graph-(i) is sine wave . Hence statement (A) is not correct

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Let us analyse option (B)

(B) For wave travelling left , grpah-(iv) is correct . For wave travelling right , graph-(iv) is correct

Above statement is true .

As mentioned earlier whether the wave is going towards left or right , snapshot at t = 0 is sine wave.

Corresponding pressure wave is negative cosine wave as given in graph-(iv)

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As per these explanation given for option (A) and option (B) , we can realise that other options are all false statment

Answered by Thiyagarajan K | 08 Feb, 2023, 09:08: PM

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