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JEE Main 2026 (2 Apr, Shift 2) · Superposition, Coherence & Intensity

Superposition, Coherence & Intensity question from JEE Main 2026 (2 Apr, Shift 2)

Q18JEE Main 2026 · 2 APR · SHIFT 2Medium

Superposition, Coherence & Intensity

In a Young's double slit experiment, the intensity at some point on the screen is found to be 34\frac{3}{4} times of the maximum of the interference pattern. The path difference between the interfering waves at this point is λx\frac{\lambda}{x} where λ\lambda is wavelength of the incident light. The value of xx is _______.

Numerical answer type. Work it out, then open the answer.

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Answer: 6

  1. I=Imaxcos⁡2ϕ2=34Imax⇒cos⁡ϕ2=32I = I_{max}\cos^2\frac{\phi}{2} = \frac{3}{4}I_{max} \Rightarrow \cos\frac{\phi}{2} = \frac{\sqrt{3}}{2}
  2. ϕ2=π6⇒ϕ=π3\frac{\phi}{2} = \frac{\pi}{6} \Rightarrow \phi = \frac{\pi}{3}
  3. Path difference Δx=λ2πϕ=λ6\Delta x = \frac{\lambda}{2\pi}\phi = \frac{\lambda}{6}
  4. So x=6x = 6.
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