chapter 18: ray optics lisa & becky. ray model of light light rays travel in straight lines ...
TRANSCRIPT
![Page 1: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/1.jpg)
Chapter 18: Ray Optics
Lisa & Becky
![Page 2: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/2.jpg)
Ray Model of Light
Light rays travel in straight lines Light rays cross but do not interact Light rays travel forever unless they interact with
matter Object is a source of light rays
Point source– comes from one point (laser) Extended source– collection of points (light bulb)
Light sees by focusing a group of rays The eye inverts the object, but the brain flips it back
upright
![Page 3: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/3.jpg)
The Pinhole Camera
A light proof box has a single hole Film sensitive to light is placed at the back Each point on the object illuminates a
single point on the film The image is inverted
![Page 4: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/4.jpg)
Types of Reflection
Specular- Reflection off of a smooth surface (mirror)
Diffuse- Reflection off of a jagged surface
![Page 5: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/5.jpg)
Reflection
Angle of incidence = Angle of reflection Angle of incidence- angle between the ray and the line
perpendicular to the surface (normal) Angle of reflection- angle between the reflected ray and
the normal
![Page 6: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/6.jpg)
Plane Mirrors
A plane mirror is a flat mirror s’ = s The rays bouncing off the mirror enter our
eye, but we see if behind the mirror, at A’
![Page 7: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/7.jpg)
Refraction
The bending of light when it moves from one medium to another
Snell’s Law- the angle of refraction depends on the refractive index (n) of the medium
the angles used are always from the normal
![Page 8: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/8.jpg)
Total Internal Reflection
When all the light reflects back into the medium Critical angle- the angle the light must refract at in order
to have total internal reflection Critical angle when theta2 = 90 degrees There is no TIR if n2 > n1
![Page 9: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/9.jpg)
Dispersion
Dispersion- index of refraction varies slightly with color
This means it varies slightly with wavelength
N is larger when the wavelength is shorter
Violet light refracts more than red light
![Page 10: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/10.jpg)
Thin Lenses Lens- transparent material that uses refraction of life at curved
surfaces to form an image Ray tracing- the pictorial method to finding an image Converging lens- Causes the ray to refract towards optical axis
Thicker in the middle Focal point- Common point through which initially parallel rays pass Focal length- distance from the lens to the focal point Diverging lens- Causes rays to refract away from optical axis
Thinner in the middle Virtual image- has the same orientation of the object Real image- inverted from the image
![Page 11: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/11.jpg)
RAY TRACING!!!!
![Page 12: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/12.jpg)
1. Parallel to optical axis and bends through far focal point2. Through near focal point and bends parallel to optical axis3. Through the center of the lens and does not bend
1
2
3
Converging LensReal Image
![Page 13: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/13.jpg)
Converging LensVirtual Image
To draw the rays you follow the same rules as before. However, the raysnever meet, so you trace them backwards to find where they will intersect.
![Page 14: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/14.jpg)
Diverging LensVirtual Image (ALWAYS!)
Follow the same rules and trace backwards to find where the rays meet
![Page 15: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/15.jpg)
Concave MirrorReal Image
1. Parallel to optical axis, reflects off and goes through focal point2. Goes through focal point and reflects parallel to axis3. Goes to center and reflects at the same angle
1
23
![Page 16: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/16.jpg)
Concave MirrorVirtual Image
Follow the same rules and extend backwards to see where rays meet
![Page 17: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/17.jpg)
Convex MirrorVirtual Image (ALWAYS!)
Follow the same rules and extend backwards to find where rays meet
![Page 18: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/18.jpg)
Now try problem 15 on page 611, and 29
on page 612
![Page 19: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/19.jpg)
![Page 20: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/20.jpg)
![Page 21: Chapter 18: Ray Optics Lisa & Becky. Ray Model of Light Light rays travel in straight lines Light rays cross but do not interact Light rays travel](https://reader034.vdocuments.net/reader034/viewer/2022052414/56649e485503460f94b3ba69/html5/thumbnails/21.jpg)
Good Luck on the Final!
BYEEEE!