This document provides a summary of key concepts from Chapter 33 on the nature and propagation of light. It discusses: 1) Light exhibits properties of both waves and particles. Rays are perpendicular to wavefronts. Reflection and refraction occur when light passes from one medium to another according to Snell's law. 2) Total internal reflection occurs when light passes from an optically dense to a rare medium at an angle greater than the critical angle. It is used in applications like binoculars and fiber optics. 3) Polarization results when light vibrates in only one direction. Polarized light interacts with polarizing filters according to Malus's law. Reflection at Brewster's angle produces