Question 281: Waves Optics

Question

A plate of refractive index 1.6 is introduced in the path of light from one of the slits in Young's double slit experiment then

Accepted Answer

When a thin plate of refractive index $n$ is introduced in front of one of the slits in YoungÃ¢ÂÂs double-slit experiment, it adds an extra optical path (and hence a phase difference) to the light coming from that slit. This shifts the entire interference pattern on the screen but does not change the fringe spacing or make the pattern disappear.
Fringe width does not change
because it depends on the slit separation and the wavelength in air, not on a uniform phase shift introduced in one path.
Number of visible fringes does not necessarily decrease
(as long as the plate is not too thick to cause excessive absorption or other effects).
The interference pattern does not vanish
unless coherence is destroyed (e.g., by scattering or large thickness variations).
The net effect
of introducing a uniform optical path difference in one slit is a lateral shift of the central maximum (and all fringes)
toward the slit with the plate
.
Hence the correct statement is :
(B) The central maximum will shift towards the side on which the plate is introduced.

Answer

the fringe width towards the side of the plate will decrease.

Answer

the central maximum will shift towards this side

Answer

number of fringes seen will decrease.

Answer

interference pattern will disappear.

Waves Optics

A plate of refractive index 1.6 is introduced in the path of light from one of the slits in Young's double slit experiment then

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