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JEE Main 2022 (28 Jun, Shift 2) · YDSE: Film, Medium & Two Wavelengths

YDSE: Film, Medium & Two Wavelengths question from JEE Main 2022 (28 Jun, Shift 2)

Q50JEE Main 2022 · 28 JUN · SHIFT 2Easy

YDSE: Film, Medium & Two Wavelengths

In a Young's double slit experiment, an angular width of the fringe is 0.35∘^\circ on a screen placed at 2 m away for particular wavelength of 450 nm. The angular width of the fringe, when whole system is immersed in a medium of refractive index 7/5, is 1α\frac{1}{\alpha}. The value of α\alpha is ___________.

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

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Answer: 4

  1. Angular width θ=λd\theta = \frac{\lambda}{d}; in a medium θ′=θμ\theta' = \frac{\theta}{\mu}.
  2. θ′=0.35∘7/5=0.25∘=14\theta' = \frac{0.35^\circ}{7/5} = 0.25^\circ = \frac{1}{4}
  3. So α=4\alpha = 4.
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