In a Newton's-rings experiment, a plano-convex glass (n = 1.52) lens having radius r = 4.20 cm is placed on a flat plate as shown in the figure below. When light of wavelength = 640 nm is incident normally, 44 bright rings are observed, with the last one precisely on the edge of the lens. (a) What is the radius R of curvature of the convex surface of the lens? Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully. m (b) What is the focal length of the lens?