1. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Light and Optical Phenomenon Light and Colors Physics 102 Goderya Chapter(s): 26 Learning Outcomes: 1,5,10,11,12

2. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Optical Phenomenon Electromagnetic Spectrum Transparent and Opaque Materials Color Why the Sky is Blue, Sunsets are Red, and Clouds are White Diffraction Interference of Light

3. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Light Waves Light is the only thing we can see originates from the accelerated motion of electrons electromagnetic phenomenon

4. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Electromagnetic Spectrum Electromagnetic wave made up of vibrating electric and magnetic fields

5. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Electromagnetic Spectrum Electromagnetic spectrum classification of electromagnetic waves according to frequency –lowest frequency of light we can see appears red –highest frequency of light we can see appears violet –higher frequency of light is ultraviolet—more energetic and causes sunburns –beyond are X-ray and gamma ray no sharp boundary between regions

6. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Color physiological experience in the eye of the beholder

7. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Color Selective reflection We see the color of a rose by the light it reflects.

8. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Color Color of transparent object depends on color of light it transmits. colored glass is warmed due to the energy of absorbed light illuminating the glass

9. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Color Mixed colored lights Distribution of solar frequencies is uneven –most intense in yellow-green portion (where our eyes are most sensitive)

10. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Color Additive primary colors red, green, and blue produce any color in the spectrum

11. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Color Subtractive primary colors combination of two of the three additive primary colors –red + blue = magenta –red + green = yellow –blue + green = cyan

12. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Color The shadows of the golf ball are subtractive Magenta (opposite of green) Cyan (opposite of red) Yellow (opposite of blue)

13. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Color Subtractive primaries are complementary to additive primaries. magenta + green = white = red + blue + green yellow + blue = white + red + green + blue example: color printing

14. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Color Only three colors of ink (plus black) are used to print color photographs—(a) magenta, (b) yellow, (c) cyan, which when combined produce the colors shown in (d). The addition of black (e) produces the finished result (f).

15. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Why the Sky is Blue

16. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Why Sunsets are Red Light that is least scattered is light of low frequencies, which best travel through air. red orange yellow

17. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Why Clouds are White Clouds clusters of various sizes of water droplets

18. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Diffraction bending of waves by means other than reflection and refraction property of all kinds of waves seen around edges of many shadows

19. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Diffraction Waves diffract after passing through a narrow opening. Plane waves passing through openings of various sizes. The smaller the opening, the greater the bending of the waves at the edges.

20. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Diffraction Amount of diffraction depends on wavelength of the wave compared to the size of the obstruction that casts the shadow.

21. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Interference of Light Superposition of waves

22. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley Interference of Light Interference colors Note the colors in the bubble are subtractive primaries—magentas, yellows, and cyans.