When a thin sheet of transparent material is placed in front of one of the slits in Young's double-slit experiment, the interference pattern formed by the overlapping waves will be affected, leading to changes in the fringe width. The specific changes depend on the properties of the material and its effect on the light passing through it. Here are a few possibilities:
Change in Fringe Separation: The presence of the thin sheet can alter the phase of the light passing through it, resulting in a phase difference between the waves from the two slits. This phase difference can lead to a change in the fringe separation or fringe width. The exact nature of the change depends on factors such as the refractive index and thickness of the material.
Shift in the Interference Pattern: If the thin sheet introduces a phase difference between the two waves, it can cause a shift in the entire interference pattern. The fringe pattern may move laterally, resulting in a displacement of the entire pattern.
Attenuation or Absorption: The transparent material may absorb or attenuate certain wavelengths of light more than others. This selective absorption can lead to a reduction in the intensity of specific fringes or a modification in their visibility. Consequently, the fringe width may appear narrower or broader depending on the wavelengths affected.
It's important to note that the specific effect on the interference pattern will vary based on the properties of the material and the characteristics of the incident light. The refractive index, thickness, and wavelength-dependent behavior of the material play significant roles in determining the alterations in the fringe width and overall interference pattern.