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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Characteristics of Light Chapter 14 Electromagnetic Waves An electromagnetic wave is a wave that consists of oscillating electric and magnetic fields, which radiate outward from the source at the speed of light. Light is a form of electromagnetic radiation. The electromagnetic spectrum includes more than visible light.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Characteristics of Light Chapter 14 Electromagnetic Waves, continued Electromagnetic waves vary depending on frequency and wavelength. All electromagnetic waves move at the speed of light. The speed of light, c, equals c = 3.00  10 8 m/s Wave Speed Equation c = f speed of light = frequency  wavelength

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Characteristics of Light Chapter 14 Electromagnetic Waves, continued Waves can be approximated as rays. This approach to analyzing waves is called Huygens’ principle. Lines drawn tangent to the crest (or trough) of a wave are called wave fronts. In the ray approximation, lines, called rays, are drawn perpendicular to the wave front.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Characteristics of Light Chapter 14 Electromagnetic Waves, continued Illuminance decreases as the square of the distance from the source. The rate at which light is emitted from a source is called the luminous flux and is measured in lumens (lm).

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Flat Mirrors Chapter 14 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 Section 2 Flat Mirrors Chapter 14 Reflection of Light, continued The angle of incidence is the the angle between a ray that strikes a surface and the line perpendicular to that surface at the point of contact. The angle of reflection is the angle formed by the line perpendicular to a surface and the direction in which a reflected ray moves. The angle of incidence and the angle of reflection are always equal.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Flat Mirrors Chapter 14 Flat Mirrors Flat mirrors form virtual images that are the same distance from the mirror’s surface as the object is. The image formed by rays that appear to come from the image point behind the mirror—but never really do—is called a virtual image. A virtual image can never be displayed on a physical surface.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Curved Mirrors Chapter 14 Concave Spherical Mirrors A concave spherical mirror is a mirror whose reflecting surface is a segment of the inside of a sphere. Concave mirrors can be used to form real images. A real image is an image formed when rays of light actually pass through a point on the image. Real images can be projected onto a screen.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Curved Mirrors Chapter 14 Concave 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 Section 3 Curved Mirrors Chapter 14 Concave Spherical Mirrors, continued The Equation for Magnification relates image height or distance to object height or distance, respectively.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Curved Mirrors Chapter 14 Concave Spherical Mirrors, continued Ray diagrams can be used for checking values calculated from the mirror and magnification equations for concave spherical mirrors. Concave mirrors can produce both real and virtual images.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Curved Mirrors Chapter 14 Convex Spherical Mirrors A convex spherical mirror is a mirror whose reflecting surface is outward-curved segment of a sphere. Light rays diverge upon reflection from a convex mirror, forming a virtual image that is always smaller than the object.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Curved Mirrors Chapter 14 Parabolic Mirrors Images created by spherical mirrors suffer from spherical aberration. Spherical aberration occurs when parallel rays far from the principal axis converge away from the mirrors focal point. Parabolic mirrors eliminate spherical aberration. All parallel rays converge at the focal point of a parabolic mirror.

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Color and Polarization Chapter 14 Color, continued Subtractive primary colors filter out all light when combined. Pigments can be produced by combining subtractive colors (magenta, yellow, and cyan).

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 4 Color and Polarization Chapter 14 Polarization of Light Waves Linear polarization is the alignment of electro- magnetic waves in such a way that the vibrations of the electric fields in each of the waves are parallel to each other. Light can be linearly polarized through transmission. The line along which light is polarized is called the transmission axis of that substance.