wave optices.pptx for grade 12 american

It's a power point slides to show the principles of wave optics

1. Wave optics Grade 9

2. Ray model Wave front model Ray model a model of waves in which you draw only the moving crests of a wave. a model of waves that uses an arrow called a ray to represent the direction the wave is traveling. Rays are always drawn perpendicular to the wave fronts. Ray models look similar to electric fields and magnetic fields.

3. Diffraction

4. Diffraction : A change in the direction of a wave when the wave encounters an obstacle, an opening, or an edge Wave front , and ray model represent wave but don’t explain diffraction

5.   Huygens’ wave model  is a model that represents every point on a wave front as a source of semicircular wavelets that spread out in the forward direction at the speed of the wave. A new wave front is tangent to all of the wavelets. You can use Huygens’ wave model to understand diffraction and other wave phenomena.

6. Sound Bends Around Corners If someone is playing music in another room, you can hear the music even if you are not standing at the doorway. Sound (longer wavelength) Light Does Not Bend Around Corners For light, large obstructions cast sharp shadows. The light waves do not bend around the corner as sound waves do. The wavelength of light is very small compared to the door—less than a millionth the size!

7. Light interactions 1 2 3 4

8. Reflection The change in direction of light waves at a surface that causes it to move away from the surface

9. The texture of a surface affects how it reflects light The manner in which light is reflected from a surface depends on the surface’s smoothness. rough, textured surface , smooth, shiny surfaces Ex: paper, cloth, or unpolished wood a mirror or water Light reflected in many different directions is reflected in one direction only This type of reflection is called diffuse reflection This type of reflection is called specular reflection

10. when incoming rays of light strike a smooth reflecting surface, such as a polished table or mirror, at an angle close to the surface, angle of incidence angle of reflection the angle between a ray that strikes a surface and the line perpendicular to that surface at the point of contact the angle formed by the line perpendicular to a surface and the direction in which a reflected ray moves Normal Line :Is a straight line is drawn perpendicular to the reflecting surface at the point where the incoming ray strikes the surface, Incoming and reflected angles are equal