When Light is reflected between a spherical surface and an adjacent touching flat surface, an interference pattern is formed. This phenomenon is called Newton’s Rings. The apparatus required to view this interference is called Newton’s Rings Apparatus.
In Newton’s Rings Apparatus, the light from the Condenser lens incidents on the plane glass inclined at 45 degrees and gets reflected vertically downwards and falls on the combination of palno convex lens and plain glass. Some portion of the light is reflected from the lower convex side of the lens and some portion of light is reflected from the upper side of the plain glass plate. A phase difference is created between the two wave fronts that gives rise to dark and bright concentric rings which are viewed through the microscope provided with a high quality Achromatic objective, a Ramsdons eyepiece and a cross line graticule. The diameter of the rings can be measured using the micrometer.
Sigma Newton’s Rings Apparatus is compact in design; consists of a heavy cast iron base with 2 levelling screws. This base carries a 4″x4″ steel box in which the sodium lamp is suspended from a rectangular aluminium top.
- Least count of the micrometer provided is 0.01mm.
- Micrometer slide total travel distance is 0-20mm.