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Section 1 Characteristics of Light. Chapter 13. Preview. Objectives Electromagnetic Waves. Section 1 Characteristics of Light. Chapter 13. Objectives. Identify the components of the electromagnetic spectrum. Calculate the frequency or wavelength of electromagnetic radiation.

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  1. Section 1 Characteristics of Light Chapter 13 Preview • Objectives • Electromagnetic Waves

  2. Section 1 Characteristics of Light Chapter 13 Objectives • Identifythe components of the electromagnetic spectrum. • Calculatethe frequency or wavelength of electromagnetic radiation. • Recognizethat light has a finite speed. • Describehow the brightness of a light source is affected by distance.

  3. Section 1 Characteristics of Light Chapter 13 Electromagnetic Waves • An electromagnetic waveis 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.

  4. Section 1 Characteristics of Light Chapter 13 The Electromagnetic Spectrum

  5. Section 1 Characteristics of Light Chapter 13 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  108 m/s • Wave Speed Equation c = f speed of light = frequency  wavelength

  6. Section 1 Characteristics of Light Chapter 13 Electromagnetic Waves Click below to watch the Visual Concept. Visual Concept

  7. Section 1 Characteristics of Light Chapter 13 Electromagnetic Waves, continued • Waves can be approximated as rays. This approach to analyzing waves is calledHuygens’ principle. • Lines drawn tangent to the crest (or trough) of a wave are calledwave fronts. • In theray approximation, lines, calledrays, are drawn perpendicular to the wave front.

  8. Section 1 Characteristics of Light Chapter 13 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 theluminous fluxand is measured inlumens (lm).

  9. Chapter 13 Section 2 Flat Mirrors Preview • Objectives • Reflection of Light • Flat Mirrors

  10. Chapter 13 Section 2 Flat Mirrors Objectives • Distinguishbetween specular and diffuse reflection of light. • Applythe law of reflection for flat mirrors. • Describe the nature of images formed by flat mirrors.

  11. Chapter 13 Section 2 Flat Mirrors Reflection of Light • Reflectionis the change in direction of an electromagnetic wave at a surface that causes it tomove away from the surface. • The texture of a surface affects how it reflects light. • Diffuse reflectionis reflection from a rough, texture surface such as paper or unpolished wood. • Specular reflectionis reflection from a smooth, shiny surface such as a mirror or a water surface.

  12. Chapter 13 Section 2 Flat Mirrors Reflection of Light, continued • The angle of incidenceis the the angle between a ray that strikes a surface and the line perpendicular to that surface at the point of contact. • Theangle 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.

  13. Chapter 13 Section 2 Flat Mirrors Angle of Incidence and Angle of Reflection Click below to watch the Visual Concept. Visual Concept

  14. Chapter 13 Section 2 Flat Mirrors Flat Mirrors • Flat mirrorsform 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 avirtual image. • A virtual image can never be displayed on a physical surface.

  15. Chapter 13 Section 2 Flat Mirrors Image Formation by a Flat Mirror

  16. Chapter 13 Section 2 Flat Mirrors Comparing Real and Virtual Images Click below to watch the Visual Concept. Visual Concept

  17. Chapter 13 Section 3 Curved Mirrors Preview • Objectives • Concave Spherical Mirrors • Sample Problem • Parabolic Mirrors

  18. Chapter 13 Section 3 Curved Mirrors Objectives • Calculatedistances and focal lengths using the mirror equation for concave and convex spherical mirrors. • Drawray diagrams to find the image distance and magnification for concave and convex spherical mirrors. • Distinguishbetween real and virtual images. • Describehow parabolic mirrors differ fromspherical mirrors.

  19. Chapter 13 Section 3 Curved Mirrors 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. • Areal imageis an image formed when rays of light actually pass through a point on the image. Real images can be projected onto a screen.

  20. Chapter 13 Section 3 Curved Mirrors Image Formation by a Concave Spherical Mirror

  21. Chapter 13 Section 3 Curved Mirrors Concave Spherical Mirrors, continued • The Mirror Equation relates object distance (p), image distance (q), and focal length (f) of a spherical mirror.

  22. Chapter 13 Section 3 Curved Mirrors Concave Spherical Mirrors, continued • The Equation for Magnification relates image height or distance to object height or distance, respectively.

  23. Chapter 13 Section 3 Curved Mirrors Rules for Drawing Reference Rays for Mirrors Click below to watch the Visual Concept. Visual Concept

  24. Chapter 13 Section 3 Curved Mirrors 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.

  25. Chapter 13 Section 3 Curved Mirrors Ray Tracing for a Concave Spherical Mirror Click below to watch the Visual Concept. Visual Concept

  26. Chapter 13 Section 3 Curved Mirrors Sample Problem Imaging with Concave Mirrors A concave spherical mirror has a focal length of 10.0 cm. Locate the image of a pencil that is placed upright 30.0 cm from the mirror. Find the magnification of the image. Draw a ray diagram to confirm your answer.

  27. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued Imaging with Concave Mirrors • Determine the sign and magnitude of the focal length and object size. f = +10.0 cm p = +30.0 cm The mirror is concave, so f is positive. The object is in front of the mirror, so p is positive.

  28. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued Imaging with Concave Mirrors 2. Draw a ray diagram using the rules for drawing reference rays.

  29. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued Imaging with Concave Mirrors 3. Use the mirror equation to relate the object and image distances to the focal length. 4. Use the magnification equation in terms of object and image distances.

  30. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued 5. Rearrange the equation to isolate the image distance, and calculate. Subtract the reciprocal of the object distance from the reciprocal of the focal length to obtain an expression for the unknown image distance.

  31. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued Substitute the values for f and p into the mirror equation and the magnification equation to find the image distance and magnification.

  32. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued • Evaluate your answer in terms of the image location and size. The image appears between the focal point (10.0 cm) and the center of curvature (20.0 cm), as confirmed by the ray diagram. The image is smaller than the object and inverted (–1 < M < 0), as is also confirmed by the ray diagram. The image is therefore real.

  33. Chapter 13 Section 3 Curved Mirrors Convex Spherical Mirrors • Aconvex spherical mirroris 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.

  34. Chapter 13 Section 3 Curved Mirrors Image Formation by a Convex Spherical Mirror

  35. Chapter 13 Section 3 Curved Mirrors Sample Problem Convex Mirrors An upright pencil is placed in front of a convex spherical mirror with a focal length of 8.00 cm. An erect image 2.50 cm tall is formed 4.44 cm behind the mirror. Find the position of the object, the magnification of the image, and the height of the pencil.

  36. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued Convex Mirrors Given: Because the mirror is convex, the focal length is negative. The image is behind the mirror, so q is also negative. f = –8.00 cm q = –4.44 cm h’ = 2.50 cm Unknown: p = ? h = ?

  37. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued Convex Mirrors Diagram:

  38. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued Convex Mirrors 2. Plan Choose an equation or situation: Use the mirror equation and the magnification formula. Rearrange the equation to isolate the unknown:

  39. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued Convex Mirrors 3. Calculate Substitute the values into the equation and solve:

  40. Chapter 13 Section 3 Curved Mirrors Sample Problem, continued Convex Mirrors 3. Calculate, continued Substitute the values for p and q to find the magnifi-cation of the image. Substitute the values for p, q, and h’ to find the height of the object.

  41. Chapter 13 Section 3 Curved Mirrors Ray Tracing for a Convex Spherical Mirror Click below to watch the Visual Concept. Visual Concept

  42. Chapter 13 Section 3 Curved Mirrors 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 aparabolic mirror.

  43. Chapter 13 Section 3 Curved Mirrors Spherical Aberration and Parabolic Mirrors

  44. Chapter 13 Section 3 Curved Mirrors Reflecting Telescope Click below to watch the Visual Concept. Visual Concept

  45. Chapter 13 Section 4 Color and Polarization Preview • Objectives • Color • Polarization of Light Waves

  46. Chapter 13 Section 4 Color and Polarization Objectives • Recognizehow additive colors affect the color of light. • Recognizehow pigments affect the color of reflected light. • Explainhow linearly polarized light is formed and detected.

  47. Chapter 13 Section 4 Color and Polarization Color • Additive primary colorsproduce white light when combined. • Light of different colors can be produced by adding light consisting of the primary additive colors (red, green, and blue).

  48. Chapter 13 Section 4 Color and Polarization Additive Color Mixing Click below to watch the Visual Concept. Visual Concept

  49. Chapter 13 Section 4 Color and Polarization Color, continued • Subtractive primary colors filter out all light when combined. • Pigments can be produced by combining subtractive colors (magenta, yellow, and cyan).

  50. Chapter 13 Section 4 Color and Polarization Subtractive Color Mixing Click below to watch the Visual Concept. Visual Concept

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