Light: Geometric Optics Chapter 23

23-1 Ray Model of Light Light travels in a straight line so a ray model is used to show what is happening to the light This model assumes light to travel in a straight line and is represented by narrow lines called light rays

23-2 Reflection from a Plane Mirror The Angle of reflection equals the angle of incidence

Diffuse reflection When light is incident upon a rough surface, microscopically rough

Image The image is what is seen in the mirror

Virtual image Real image

23-3 Formation of Images by Spherical Mirrors Convex – reflects from the outside of the sphere, rearview mirrors Concave – reflects from the inside of the sphere, cosmetic mirrors

Focal Point & Focal Length

Image Formation-Ray Diagrams

Mirror Equation & Magnification

Mirror Equation Where d o is the object distance d i is the image distance f is the focal length

Magnification Equation Where m is the magnification h o is the object height h i is the image height d o is the object distance d i is the image distance

Sign gives the correct location and orientations of the image If h i + then upright, - inverted If d i or d o + then in front of mirror, - behind mirror

Objects closer to concave mirror

Convex Mirror Focal point behind the mirror Focal length is negative