1. Notes on Chapter 30 Lenses
Conceptual Physics
Notes on Chapter 30
Lenses

2. Any piece of glass that bends parallel rays of light is a Lens
Lenses
Any piece of glass that bends parallel rays of light is a Lens

3. Lenses
If the parallel rays come together than the lens is a Converging Lens

4. Lenses
If the parallel rays spread apart, then the lens is a Diverging Lens

5. Lenses
Three rays make up the primary rays through a lens. Two are needed to form the image.

6. Lenses
Major (Principal) axis - Line that runs through the center of the lens.
a. Focal Point (F) is on this line.
b. Focal Length is on this line.
c. Center of curvature is on this line.

7. Lenses Ray #1 goes through center of lens.
Ray #2 starts out parallel to lens and bends to focal point on other side of lens.
Ray #3 goes through focal point to lens and then parallel to major axis.

8. Lenses
Ray #1 goes through center of lens.

9. Lenses
Ray #2 coming in horizontally from the tip of the arrow, goes through the focal point.                                          

10. Lenses
Ray #3 going from the tip of the arrow to the near focal point will come out horizontally

11. Lenses
Images
If we combine the two we get the following picture.
                                                                              

12. (Mirror is a good example)
Lenses
REAL AND VIRTUAL IMAGES
Real images are formed when the object is far enough away to be beyond the focal point to be focused on a screen.
Virtual images appear to be behind the glass - but there is no light behind the glass
(Mirror is a good example)

13. Lenses
The Eye:
Parts
Iris
Pupil
Cornea
Retina

14. Lenses
Defects called Farsighted and Nearsighted can cause your vision to be blurred.

15. Lenses
Farsighted people see images blurred due to lens making the image form “behind” the retina.

16. Lenses
Nearsighted people see images blurred due to lens making the image form before the retina.

17. Lenses
Other defects can be Spherical Aberration. All parallel rays do not converge to one single point.

18. Lenses
Chromatic Aberration is do to different colors and speeds in lenses.