Metal cast construction provided with sodium lamp, microscope, power supply & optics are housed in single piece compact body (stand alone setup).
Optical glass plate mounted at 45° (no adjustment required).
Smooth moving collimating facility.
Quick adjustment, good quality, well defined distinct fringes.

 Specifications
Micrometer: 0.01 mm least count
Eyepiece: Ramsden 10X
Objective: 3x

 Principle and Working

A plano-convex lens is placed with its convex surface on the optically plane glass plate so as to enclose a thin film of air of varying thickness between the lens and the plate. Light from an extended monochromatic source is converted into a parallel beam of light by using a convex lens of short focal length and made to fall on an optically plane glass plate inclined at an angle of 45° to the vertical, where it gets reflected on to the Plano-convex lens. The wavelength of monochromatic light source is determined from the radii of the interference rings.