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MHT CET 2025 (25 Apr, Shift 2) · Biprism, Thin Films & Other Devices

Biprism, Thin Films & Other Devices question from MHT CET 2025 (25 Apr, Shift 2)

Q9MHT CET 2025 · 25 APR · SHIFT 2Easy

Biprism, Thin Films & Other Devices

In a biprism experiment a steady interference pattern is observed on the screen using a light of wavelength 5000 A˚5000\ \text{\AA}. Without disturbing the set up of the experiment, the source of light is replaced by a source of wavelength 6400 A˚6400\ \text{\AA}.

The fringe width will

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Answer: (d)

  1. β=λDd⇒β∝λ\beta = \frac{\lambda D}{d} \Rightarrow \beta \propto \lambda.
  2. β′β=64005000=1.28\frac{\beta'}{\beta} = \frac{6400}{5000} = 1.28.
  3. So the answer is (d): fringe width increases by 28%28\%.
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