On Alternative Methods of Determining Radius of Curvature Using Newton’s Rings Set up

Abstract

It well known that radius of curvature of a plano convex lens can be determined using Newton’s Rings set up making use of Interference by division of amplitude principle. The general method widely used involves measurement of diameter of several circular dark fringes. We propose two alternative methods involving different formulae. It is based on the fact that, the formation of bright and dark interference fringes is a measure of the thickness of the air film at that point. The methods use simpler geometry and the formulae are easier to derive. We present the experimental data. The results from the experiment are in agreement with results obtained through the general method.