Q. In Young’s double slit interference pattern the fringe width
A) Can be changed only by changing the wavelength of incident light
B) Can be changed only by changing the separation between the two slits
C) Can be changed either by changing the wavelength or by changing the separation between the two slits
D) Is a universal constant, hence cannot be changed
Explanation
(c) Fringe width is $\beta = \frac{D\lambda}{d}$ where $D$ is the distance of the slits from the screen, $d$ is the separation of the slits and $\lambda$, the wavelength
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.