1 In a Newton's-??rings experiment, a plano-??convex glass (n = 1.52) lens having diameter 10.0 cm is placed on a flat plate as shown in lecture notes. When 650-??nm light is incident normally, 55 bright rings are observed with the last one right on the edge of the lens.
(a) What is the radius of curvature of the convex surface of the lens?
(b) What is the focal length of the lens?
2. One leg of a Michelson interferometer contains an evacuated cylinder of length L, having glass plates on each end. A gas is slowly leaked into the cylinder until a pressure of 1 atm is reached. If N bright fringes pass on the screen when light of wavelength ? is used, what is the index of refraction of the gas?
3. Gold is the most ductile of all metals. For example, one gram of gold can be drawn into a wire 2.40 km long. What is the resistance of such a wire at 20°C? You can find the necessary reference information in your textbook.