Geometrical Optics Experiment: Finding Focal Lengths of Concave Mirror and Lenses - Prof. , Lab Reports of Physics

Download Geometrical Optics Experiment: Finding Focal Lengths of Concave Mirror and Lenses - Prof. and more Lab Reports Physics in PDF only on Docsity! Experiment 2 - Geometrical Optics 1 Experiment 2 Geometrical Optics 1 Introduction In this experiment, we will continue to explore geometrical optics by studying the optics of simple curved mirrors and lenses. 2 Background - see Pedrotti3, Sections 2-6 to 2-9 When studying the geometrical optics of mirrors or lenses one considers the following three quantities: object distance so, image distance si , and focal length f . These quantities are related by the equation 1 so + 1 si = 1 f (1) There is a convention to be followed in the definition of these quantities. For lenses, a converging lens (convex) has f > 0 while a diverging lens (concave) has f < 0. For mirrors, f > 0 for concave mirrors, and f < 0 for convex mirrors. Also by convention, we place the object to the left of the lens, with so > 0. If si > 0, it is on the right of the lens and is a real image. If si < 0 it is to the left of the lens (same side as object) and is a virtual image. One can consider the mirror as a folded over version of the lens: so is positive and on the left, but now a si > 0 is on the left (the opposite of the lens) and si < 0 is on the right, behind the mirror, and a virtual image. The focal length of a spherical mirror is simply f = R/2, where R is the radius of the mirror, and the focal length of a thin lens is given by 1 f = (n− 1) ( 1 R1 − 1 R2 ) , (2) where n is the index of refraction, and Ri are the radii of curvature of the two surfaces.