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MHT CET 2024 (9 May, Shift 2) · Reflection, Superposition & Interference

Reflection, Superposition & Interference question from MHT CET 2024 (9 May, Shift 2)

Q7MHT CET 2024 · 9 MAY · SHIFT 2Easy

Reflection, Superposition & Interference

The equations of two waves are given as

y1=asin⁡(ωt+ϕ1)y2=asin⁡(ωt+ϕ2)\begin{matrix} y_1 = a\sin(\omega t + \phi_1) \\ y_2 = a\sin(\omega t + \phi_2) \end{matrix}

If amplitude and time period of resultant wave is same as the individual waves, then (ϕ1−ϕ2)(\phi_1 - \phi_2) is

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Answer: (a)

  1. Resultant amplitude: AR2=a2+a2+2a2cos⁡ϕA_R^2 = a^2 + a^2 + 2a^2\cos\phi, with ϕ=ϕ1−ϕ2\phi = \phi_1 - \phi_2
  2. AR=a⇒a2=2a2(1+cos⁡ϕ)⇒cos⁡ϕ=−12A_R = a \Rightarrow a^2 = 2a^2(1 + \cos\phi) \Rightarrow \cos\phi = -\frac{1}{2}
  3. So the answer is (a) cos⁡−1(−12)\cos^{-1}\left(-\frac{1}{2}\right).
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