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MHT CET 2026 (19 Apr, Shift 2) · Biprism, Thin Films & Other Devices

Biprism, Thin Films & Other Devices question from MHT CET 2026 (19 Apr, Shift 2)

Q5MHT CET 2026 · 19 APR · SHIFT 2Medium

Biprism, Thin Films & Other Devices

In biprism experiment, the maximum intensity is I0I_0. If the path difference between the two interfering waves is λ3\frac{\lambda}{3}, then intensity at the point on the screen is

[sin⁡30∘=cos⁡60∘=0.5, sin⁡60∘=cos⁡30∘=3/2\sin 30^\circ = \cos 60^\circ = 0.5,\ \sin 60^\circ = \cos 30^\circ = \sqrt{3}/2]

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Answer: (a)

  1. Phase difference ϕ=2πλ⋅λ3=2π3\phi = \frac{2\pi}{\lambda}\cdot\frac{\lambda}{3} = \frac{2\pi}{3}.
  2. I=I0cos⁡2ϕ2=I0cos⁡260∘=I04I = I_0\cos^2\frac{\phi}{2} = I_0\cos^2 60^\circ = \frac{I_0}{4}.
  3. So the answer is (a) I04\frac{I_0}{4}.
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