Wave Motion 4 Question 23

22. Four harmonic waves of equal frequencies and equal intensities I0 have phase angles 0,π3,2π3 and π. When they are superposed, the intensity of the resulting wave is nI0. The value of n is

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Answer:

Correct Answer: 22. 3

Solution:

  1. Let individual amplitudes are A0 each. Amplitudes can be added by vector method.

A1=A2=A3=A4=A0

Resultant of A1 and A4 is zero. Resultant of A2 and A3 is

A=A02+A02+2A0A0cos60=3A0

This is also the net resultant.

Now, IA2

Net intensity will become 3I0.

Answer is 3 .



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