Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
In a biprism experiment, monochromatic light of wavelength ' $\lambda$ ' is used. The distance between two coherent sources ' $\mathrm{d}$ ' is kept constant. If the distance between slit and eyepiece ' $D$ ' is varied as $D_1, D_2, D_3 \& D_4$ and corresponding measured fringe widths are $Z_1, Z_2, Z_3$ and $Z_4$ then
PhysicsWave OpticsMHT CETMHT CET 2023 (13 May Shift 1)
Options:
  • A $\mathrm{Z}_1 \mathrm{D}_1=\mathrm{Z}_2 \mathrm{D}_2=\mathrm{Z}_3 \mathrm{D}_3=\mathrm{Z}_4 \mathrm{D}_4$
  • B $\frac{Z_1}{D_1}=\frac{Z_2}{D_2}=\frac{Z_3}{D_3}=\frac{Z_4}{D_4}$
  • C $\mathrm{D}_1 \sqrt{\mathrm{Z}_1}=\mathrm{D}_2 \sqrt{\mathrm{Z}_2}=\mathrm{D}_3 \sqrt{\mathrm{Z}_3}=\mathrm{D}_4 \sqrt{\mathrm{Z}_4}$
  • D $\quad Z_1 \sqrt{D_1}=Z_2 \sqrt{D_2}=Z_3 \sqrt{D_3}=Z_4 \sqrt{D_4}$
Solution:
2353 Upvotes Verified Answer
The correct answer is: $\frac{Z_1}{D_1}=\frac{Z_2}{D_2}=\frac{Z_3}{D_3}=\frac{Z_4}{D_4}$
Fringe width $Z=\frac{\lambda D}{d}$
$\therefore \quad \frac{Z}{D}=\frac{\lambda}{d}=$ constant, as $\lambda$ and $d$ are constant
$$
\therefore \quad \frac{Z_1}{D_1}=\frac{Z_2}{D_2}=\frac{Z_3}{D_3}=\frac{Z_4}{D_4}
$$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.