Explain how newton's rings are obtained in the laboratory?Why newton's rings are circular in shape?
Newton's rings are essentially a pattern of interferenceof light. They are produced when the light is reflected between two surfaces - a spherical surface and an adjacent flat surface. In the resultant interference pattern, areas of same brightness are determined by the difference of phases of waves, thickness of the medium material traversed (e.g. air). These are points that are equidistant from the point of contact of the two surfaces, i.e. circles.