Determination of wave length of light and thickness of thin transparent sheet (mica)

Fig- shows the experimental arrangement. Light from monochromatic source is made to fall on a thin slit mounted vertically on a rigid optical bench fitted with a scale. The biprism and the screen (in this case an eye piece) are also mounted vertically. The eye piece can be moved in the plane perpendicular to the axis of bench using a micrometer based translation stage. A convex lens of small focal length is required to determine the separation between the two virtual sources.

                 
              Fig.11.1.2:Experimental Set-Up: Fresnel Biprism Experiment