Light.notebook May 03, 2016

Transcription

1 Unit 4 Light LIGHT.1 Describe the ray model of light LIGHT.2 Predict the effect of distance on light s illuminance LIGHT.3 Explain polarization and the Doppler effect LIGHT.4 Describe interference and diffraction. 19.1,2 LIGHT.5 Explain and use the law of reflection LIGHT.6 Locate and describe images formed by mirrors LIGHT.7 Solve problems involving Snell s Law LIGHT.8 Describe how images are formed from lenses using ray diagrams Apr 21 3:17 PM Apr 21 3:47 PM

2 The Spectrum we see Apr 22 6:50 AM THEORIES OF LIGHT Newton's theory light consists of particles called corpuscles; this theory only explained reflection and refraction. Wave theory of light (Maxwell's theory) light behaves like a wave; this explained all the properties of light such as reflection, refraction, diffraction, interference and polarization; it did not explain the photoelectric effect or radiation produced by an incandescent light. Quantum theory light has a dual nature: when light is transmitted through space or matter, it behaves like a wave; when light is emitted or absorbed, it behaves like a particle called a photon. Apr 21 5:00 PM

3 Apr 21 5:25 PM Light is an electromagnetic wave. Light is a transverse wave Apr 21 5:07 PM

4 Sound is a mechanical wave Sound is a longitudinal wave Apr 21 5:21 PM THE SPEED OF LIGHT IN A VACUUM 300,000 km/sec or 3 X 10 8 m/s FIRST DEMONSTRATION OF A FINITE SPEED OLAF ROEMER WATCHING THE MOONS OF JUPITER FIRST MEASUREMENT ALBERT MICHELSON IN 1880 ROTATING MIRROR EXPERIMENT LIGHT YEAR DISTANCE LIGHT TRAVELS IN ONE YEAR Apr 22 6:45 AM

5 Light and materials TRANSPARENT ABLE TO TRANSMIT LIGHT THROUGH, EX: GLASS, AIR OPAQUE NOT ABLE TO TRANSMIT LIGHT THROUGH, EX: METAL, ROCK TRANSLUSCENT IN BETWEEN TRANSPARENT AND OPAQUE Apr 22 6:49 AM Shadows are places where light is blocked by an opaque object UMBRA THE TOTAL PART OF THE SHADOW PENUMBRA A PARTIAL SHADOW Apr 22 6:58 AM

6 WHITE LIGHT SPLIT UP RED ORANGE YELLOW GREEN BLUE INDIGO VIOLET Apr 22 7:03 AM Color comes to our eyes from objects due to: Emission Reflection Transmission Interference Dispersion Scattering Apr 22 7:09 AM

7 Color by Reflection WHITE OBJECTS BLACK OBJECTS WHAT YOU SEE IS WHAT YOU GET Apr 22 7:13 AM Primary colors Red, Blue and Green Apr 22 7:15 AM

8 Apr 22 9:39 AM Ray model of light The ray model of light was introduced as a way to study how light interacts with matter, regardless of whether light is a particle or a wave. Apr 23 9:37 PM

9 Luminous and illuminated sources Apr 23 9:44 PM Apr 23 9:51 PM

10 REFLECTION OF LIGHT Light obeys the law of reflection that states that: "The angle of incidence is equal to the angle of reflection." Angles are measured with respect to the normal line Apr 23 9:57 PM Apr 23 10:00 PM

11 Light reflection from a smooth surface is called regular or specular reflection. Light reflection from a rough or irregular surface is called diffuse reflection. Apr 23 10:02 PM Ray diagram for plane mirror images Left Right reversal Same size Upright Virtual Apr 23 10:15 PM

12 The image is the same size as the object and the same distance behind the mirror as the object is in front of the mirror. The images formed by a plane mirror are, in truth, reflections of real objects. The images themselves are not real because no light passes through them. These images which appear to the eye to be formed by rays of light but which in truth do not exist are called virtual images. On the other hand real images are formed when rays of light actually intersect at a single point. Apr 23 10:33 PM Curved mirrors CURVED MIRRORS A curved mirror is a mirror that may be thought of as a portion of a reflecting sphere. If the inside of the spherical surface is the reflecting surface, the mirror is said to be concave or converging. If the outside portion is the reflecting surface, the mirror is convex or diverging. Apr 23 10:41 PM

13 Apr 25 11:18 PM f focal length, R radius of curvature A or V or P Center of the mirror Apr 25 11:20 PM

14 Image formation ray tracing Apr 25 11:28 PM Apr 25 11:31 PM

15 Apr 25 11:32 PM 1)Object between F and C Apr 25 11:53 PM

16 2) Object beyond C Apr 26 12:16 AM 3) Object at C Apr 25 11:55 PM

17 4) Object at F Apr 26 12:11 AM 5) Object between F and the mirror Apr 26 12:11 AM

18 Convex mirror object in front of the mirror Apr 26 12:11 AM Concave Convex Converging mirror Diverging mirror Apr 26 12:29 AM

19 Apr 26 12:30 AM THE (Curved) MIRROR EQUATION The mirror equation can be used to locate the image Where d o is the object s distance, d i is the image distance and f is the focal length. The ratio M is called the magnification, h o is the object s size and h i is the image size. Apr 27 2:08 PM