When a parallel beam of monochromatic light is incident normally on a combination of a
plano-convex lens L and a glass plate G, as shown in Fig.1, a part of each incident ray is
reflected from the lower surface of the lens, and a part, after refraction through the air film between
the lens and the plate, is reflected back from the plate surface. These two reflected rays are coherent,
hence they will interfere and produce a system of alternate dark and bright rings with the point of
contact between the lens and the plate as the center. These rings are known as Newton’s ring.
Newton Rings are formed as a result of interference between light wave reflected from the upper and lower surfaces of the air film.
-~-~~-~~~-~~-~-
Please watch: "Zone Plate (Part-1) "
https://www.youtube.com/watch?v=FCP2S5wufww
-~-~~-~~~-~~-~-
