Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Flat Mirrors Chapter 13 Reflection of Light Reflection is the change in direction of an electromagnetic wave at a surface that causes it to move away from the surface. The texture of a surface affects how it reflects light. –Diffuse reflection is reflection from a rough, texture surface such as paper or unpolished wood. –Specular reflection is reflection from a smooth, shiny surface such as a mirror or a water surface.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mirrors Lab In which mirror(s) can you make your image larger? In which mirror(s) can you make your image smaller? In which mirror(s) can you make your image remain the same size? In which mirror(s) can you make your image appear rightside up? In which mirror(s) can you make your image appear upside down? In which mirror(s) can you make your image not appear?

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 13 Angle of Incidence and Angle of Reflection Section 2 Flat Mirrors

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Flat Mirrors Chapter 13 Reflection of Light, continued The angle of incidence and the angle of reflection are always equal.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 13 Comparing Real and Virtual Images Section 2 Flat Mirrors

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 13 Image Formation by a Flat Mirror Section 2 Flat Mirrors

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Perpendicular ray Incident ray Reflected ray Ray Diagram for plane mirror:

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Flat Mirrors Chapter 13 Flat Mirrors Flat mirrors form virtual images that are the same distance from the mirror’s surface as the object is. Virtual Image PP’

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Concave and Convex Mirrors Concave and convex mirrors are curved mirrors similar to portions of a sphere. light rays Concave mirrors reflect light from their inner surface, like the inside of a spoon. Convex mirrors reflect light from their outer surface, like the outside of a spoon.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu C: Center of curvature (center of the sphere) C: Center of curvature (center of the sphere) V: Vertex The point where the principal axis intersects the mirror at a 90 degree angle V: Vertex The point where the principal axis intersects the mirror at a 90 degree angle Principal axis: the line through the center to the midpoint of the mirror F: Focus Midpoint between C and V F: Focus Midpoint between C and V F

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Focusing Light with Concave Mirrors Light rays parallel to the principal axis will be reflected through the focus. In reverse, light rays passing through the focus will be reflected parallel to the principal axis, as in a flood light. Concave mirrors can form both real and virtual images, depending on where the object is located.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 13 Rules for Drawing Reference Rays for Mirrors Section 3 Curved Mirrors

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 13 Ray Tracing for a Concave Spherical Mirror Section 3 Curved Mirrors

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Concave Mirrors: Object beyond C CF object image The image formed when an object is placed beyond C is located between C and F. It is a real, inverted image that is smaller in size than the object.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Concave Mirrors: Object at C or F What happens when an object is placed at C? What happens when an object is placed at F? The image will be formed at C also, but it will be inverted. It will be real and the same size as the object. No image will be formed. All rays will reflect parallel to the principal axis and will never converge. The image is “at infinity.”

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Concave Mirrors: Object between C and F C F object image The image formed when an object is placed between C and F is located beyond C. It is a real, inverted image that is larger in size than the object.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Concave Mirrors: Object between F and the mirror C F object image The image formed when an object is placed between F and the mirror is a virtual, upright image that is larger in size than the object.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Convex Mirrors A convex mirror has the same basic properties as a concave mirror but its focus and center are located behind the mirror. This means a convex mirror has a negative focal length (used later in the mirror equation). Light rays reflected from convex mirrors always diverge, so only virtual images will be formed. light rays

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 13 Ray Tracing for a Convex Spherical Mirror Section 3 Curved Mirrors

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Convex Mirror Diagram CF object image The image formed by a convex mirror no matter where the object is placed will be virtual, upright, and smaller than the object. As the object is moved closer to the mirror, the image will approach the size of the object.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ray diagram practice: Draw a ray diagram for an object that is 2 cm high and is located 10 cm from a concave mirror with a focal length of 6 cm. Label the object, image, object distance, image distance, center point, and focal point. Draw a ray diagram for an object that is 2 cm high and is located 4 cm from a convex mirror with a focal length of 6 cm. Label the object, image, object distance, image distance, center point, and focal point.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnification m = magnification h i = image height (negative means inverted) h o = object height m = hihi hoho By definition, Magnification is simply the ratio of image height to object height. A positive magnification means an upright image.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnification Identity: m = -di-di dodo hihi hoho = C object image, height = h i didi dodo hoho

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Curved Mirrors Chapter 13 Spherical Mirrors, continued The Mirror Equation relates object distance (p), image distance (q), and focal length (f) of a spherical mirror.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Measure the image distance & image height on each of your ray diagrams Draw a ray diagram for an object that is 2 cm high and is located 10 cm from a concave mirror with a focal length of 6 cm. Draw a ray diagram for an object that is 2 cm high and is located 4 cm from a convex mirror with a focal length of 6 cm. Calculate the actual image distance, image height & magnification for each.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mirror Equation Sample Problem Suppose AllStar, who is 3 and a half feet tall, stands 27 feet in front of a concave mirror with a radius of curvature of 20 feet. Where will his image be reflected and what will its size be? d i = h i = CF feet feet

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mirror Equation Sample Problem 2 CF Casey decides to join in the fun and she finds a convex mirror to stand in front of. She sees her image reflected 7 feet behind the mirror which has a focal length of 11 feet. Her image is 1 foot tall. Where is she standing and how tall is she? d o = h o = feet 2.75 feet

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Practice B Open books to page 462 –#1 - 4 Chapter 13 Section 1 Characteristics of Light Open books to page 466 –#1 - 6 Practice C