The document discusses different optical devices including lenses, mirrors, and prisms. It focuses on spherical mirrors, describing the two types - concave and convex mirrors. Key details are provided on the center of curvature, radius of curvature, principal axis, pole, focus, and focal length. The mirror formula relating object distance, image distance, and focal length is defined. Characteristics of images formed by concave and convex mirrors in different situations are explained. Uses of concave and convex mirrors are also noted.