2022 Wave OpticsYoung's Double Slit Experiment Medium Question 3 of 8 in Young's Double Slit Experiment

In a Young's double slit experiment, a student observes 8 fringes in a certain segment of screen when a monochromatic light of 600 nm wavelength is used. If the wavelength of light is changed to 400 nm, then the number of fringes he would observe in the same region of the screen is

A 12
B 6
C 8
D 9

The answer is A.

Solution

Fringe position $y = n\lambda\frac{D}{d}$; for the same segment of the screen, $n_1\lambda_1 = n_2\lambda_2$ $8 \times 600 = n_2 \times 400$ $n_2 = 12$

Concept fringe number vs wavelength

Young's Double Slit Experiment in past papers

8 questions from this chapter have appeared across 8 exam years.