Reflection
- 2. • Luminous objects – generate their own light (the sun) • Illuminated objects – reflect light (the moon) • Line of Sight – a line from an object or image to your eyes (light from the object travels along this line to your eyes) Slide 2 Definitions
- 3. Slide 3 Line of Sight • Both luminous & illuminated objects emit/reflect light in many directions. • Your eye sees only the very small diverging cone of rays that is coming toward it.
- 4. Slide 4 Rays of Light • Incident Ray – leaves the object and strikes the mirror • Reflected Ray – leaves mirror and strikes your eye • The reflected ray is on the line of sight from the image to your eye.
- 5. Slide 5 Law of Reflection • Angle of incidence equals angle of reflection.
- 6. Slide 6 Law of Reflection • Normal – line perpendicular to the mirror surface • Angle of incidence – angle between incident ray and normal • Angle of reflection – angle between reflected ray and normal
- 7. Law of Reflection Animation qi = qr Slide 7
- 8. Slide 8 Diffuse Reflection
- 9. Slide 9 Diffuse Reflection
- 10. Slide 10 Wet Road Glare • Driving at night on a wet roadway results in an annoying glare from oncoming headlights.
- 11. Slide 11 Observing an Image • An image is a position in space from which all reflected light appears to diverge. • Image formed by a plane mirror is called a virtual image. • Virtual images are formed in regions where there is actually no light
- 12. Slide 12 Image Location
- 13. Image Formed By Plane Mirror Slide 13 • Image is virtual. • Image is located as far behind the mirror as the object is in front of the mirror.
- 14. How Big Must the Mirror Be? Slide 14
- 15. Slide 15 Distance from Mirror Irrelevant
- 16. Slide 16 Right Angle Mirror
- 17. Slide 17 Right Angle Mirror • Formation of primary and secondary images
- 18. Slide 18 Kaleidoscope • Angles smaller than 90o produce more than 3 images
- 19. Slide 19 Kaleidoscope Applets • Hinged Mirror Applet • Image Formation Applet
- 20. Reflection Applets • Plane Mirror Image Applets • Double Mirror Images • Hinged Mirror Applet • Rainbow Applets
- 21. Law of Reflection Curved Mirrors • Angle of Incidence is equal to the angle of reflection
- 22. Converging Mirror • A series of flat mirrors can be arranged to reflect parallel light through a single point. • Increasing the number of flat mirrors causes the shape to more closely approximate a parabola and causes the reflected light to converge in a smaller area.
- 23. Parabolic vs Spherical • Close to the axis of the mirror, the parabola and the circle are almost the same shape. • Farther from axis the parabola flattens out. • It is easier and less expensive to make spherical mirrors.
- 24. Types of Curved Mirrors • A concave mirror is silvered on the inside of the sphere. • A concave mirror is also called a converging mirror because it converges parallel light. • A convex mirror is silvered on the outside of the bowl. • A convex mirror is also called a diverging mirror because it diverges parallel light.
- 25. Concave Mirror Terms • Axis • Center of Curvature • Radius of Curvature • Focus • Focal Length
- 26. Three Useful Rays • Ray parallel to the axis reflects through the focus. • Ray through the focus reflects parallel to the axis. • Ray through the center of curvature reflects back on itself.