PHYWE Newton Rings with Interference Filters and Digital Matrix Camera

Principle In the Newton's ring apparatus, monochromatic light interferes in a thin film of air between a slightly convex lens and a flat glass plate. Wavelengths are determined from the radii of the interference rings. Advantages: The colour of soap bubbles is based on: interference in thin films; use of interference optics to detect the finest differences; complex filters make quantitative measurements possible. Tasks: use of the Newton's ring apparatus to measure the diameter of the rings at different wavelengths and: determine the wavelengths for a given radius of curvature of the lens; determine the radius of curvature at given wavelengths. Learning Objectives: coherent light; phase relationship; path difference; interference in thin films; Newton's ring apparatus.