Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main 202523 JanuaryEvening Shift
Exam
JEE Main
Year
2025
Date
23 January
Shift
Evening Shift
Subject
Physics
Chapter
Wave Optics

JEE Main 2025 · 23 January · Evening Shift · Physics · Wave Optics

The width of one of the two slits in Young's double slit experiment...

The width of one of the two slits in Young's double slit experiment is d while that of the other slit is x dx \mathrm{~d}. If the ratio of the maximum to the minimum intensity in the interference pattern on the screen is 9:49: 4 then what is the value of xx ? (Assume that the field strength varies according to the slit width.)

Options

  1. A4
  2. B5
  3. C3
  4. D2

Correct answer

B. 5

Step-by-step solution

I∝( width )2(I1+I2I1−I2)2=94I1+I2I1−I2=32(x+1)d(x−1)d=32⇒3x−3=2x+2x=5\begin{aligned} & \mathrm{I} \propto(\text{ width })^2 \\ & \left(\frac{\sqrt{\mathrm{I}_1}+\sqrt{\mathrm{I}_2}}{\sqrt{\mathrm{I}_1}-\sqrt{\mathrm{I}_2}}\right)^2=\frac{9}{4} \\ & \frac{\sqrt{\mathrm{I}_1}+\sqrt{\mathrm{I}_2}}{\sqrt{\mathrm{I}_1}-\sqrt{\mathrm{I}_2}}=\frac{3}{2} \\ & \frac{(\mathrm{x}+1) \mathrm{d}}{(\mathrm{x}-1) \mathrm{d}}=\frac{3}{2} \\ & \Rightarrow 3 \mathrm{x}-3=2 \mathrm{x}+2 \\ & \mathrm{x}=5\end{aligned}
Practice Wave Optics on Quantrex Academy →

More from Wave Optics

In the List-I, four optical effects are mentioned. The physical phenomena of light which… JEE Advanced 2026In a single slit diffraction experiment, a slit of width (0.016 ± 0.002) mm is used to… JEE Advanced 2026As shown in the figure, a ray AB of unpolarized light enters from water of refractive… JEE Advanced 2026Some distant star is to be observed by some telescope of diameter of objective lens a… JEE Main 2026In a Young double slit experiment, the wavelength of incident light is 6000 Å, the… JEE Main 2026In interference experiment the path difference between two interfering waves at a point A… JEE Main 2026An unpolarized light of intensity I_o passes through polarizer and then through a certain… JEE Main 2026The maximum intensity in a Young's double slit experiment is I_0 . Distance between the… JEE Main 2026 Full Wave Optics list All JEE Main PYQs