COMEDK2024Evening ShiftPhysicsWave OpticsActual
Two narrow parallel slits illuminated by a coherent monochromatic light produces an interference pattern on a screen placed at a distance D from the slits. The separation between the dark lines of the interference pattern can be increased by
Options
- Adecreasing the distance between the screen and the slits
- Busing monochromatic light of higher frequency
- Cusing monochromatic light of a longer wavelength
- Dincreasing the distance between the slits
Correct answer
C. using monochromatic light of a longer wavelength
Step-by-step solution
The fringe width in a Young's double slit experiment is given by the formula = D d , where is the wavelength of the monochromatic light, D is the distance between the slits and the screen, and d is the separation between the two slits. The separation between the dark lines (fringe width) is directly proportional to the wavelength and the distance D , and inversely proportional to the slit separation d . To increase the fringe width , one must either increase , increase D , or decrease d . Since frequency f is relat