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Four harmonic waves of equal frequencies and equal intensities I₀ have phase angles 0, π/3, 2π/3, and π. When they are superposed, the intensity of the resulting wave is nI₀. The value of n is

1. 2
2. 3
3. 4
4. 5

Correct answer: 3

Solution

The superposition of four harmonic waves with given phase angles results in a net amplitude determined by vector addition in the complex plane. The intensity is proportional to the square of the resultant amplitude, which calculates to 3I₀.

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