Physics Circle home Student Login

Home›Chapters›Wave Optics PYQs›YDSE: Film, Medium & Two Wavelengths›Question 13

JEE Main 2026 (21 Jan, Shift 1) · YDSE: Film, Medium & Two Wavelengths

YDSE: Film, Medium & Two Wavelengths question from JEE Main 2026 (21 Jan, Shift 1)

Q13JEE Main 2026 · 21 JAN · SHIFT 1Medium

YDSE: Film, Medium & Two Wavelengths

In a double slit experiment the distance between the slits is 0.1 cm and the screen is placed at 50 cm from the slits plane. When one slit is covered with a transparent sheet having thickness tt and refractive index n(=1.5)n(= 1.5), the central fringe shifts by 0.2 cm. The value of tt is

______ cm.

Show answer and solution

Answer: (b)

  1. Shift y=(n−1)tDd⇒t=yd(n−1)Dy = \frac{(n-1)tD}{d} \Rightarrow t = \frac{yd}{(n-1)D}.
  2. t=0.2×0.10.5×50=8×10−4t = \frac{0.2\times0.1}{0.5\times50} = 8\times10^{-4} cm
  3. So the answer is (b) 8×10−48\times10^{-4} cm.
Report a mistake

More questions on YDSE: Film, Medium & Two Wavelengths