1. 1 32 Optical Images image formation reflection & refraction mirror & lens equations Human eye Spherical aberration Chromatic aberration

2. 2 image formation real image: rays converge to a point Ex. sun’s rays focused by magnifier virtual image: apparent source of light divergence Ex. image seen in mirror

3. 3 Plane Mirror Image distances measured from mirror & axis image height hi = object height ho object distance do = image distance di

4. 44 concave mirror images

5. 55 convex mirror images always “virtual”, “upright”, “diminished”

6. 66 lens images

7. 77 Lens & Mirror Equation relate do, di & f. lateral magnification (LM) = hi/ho. you must learn the sign conventions to use these formulas

8. 8 imbedded object image distance < object distance

9. 99 lens power power = 1/(focal-length(meters)) unit: [D, diopters, 1/m] used for corrective lenses Ex. near-sighted person P = -5.0D f = 1/P = 1/(-5) = -0.2m = -20cm.

10. 10 human eye average index of refraction ~ 1.4

11. 11 Far Sighted Eye correction requires converging lens

12. 12 near sighted eye correction requires diverging lens

13. 13 Spherical Aberration Spherical aberration: light striking near edge focus at different points than light striking near center

14. 14 Chromatic Aberration Chromatic aberration: different colors focus at different points

15. 15 Summary Image formation by lenses & mirrors Real/virtual, orientation, magnification. Near & far-sighted problem & correction Spherical & chromatic aberration

16. 16 2. A document is sealed in a glass cube (n=1.5) at a depth of 10cm from one surface. Calculate s’ and m. Object is in n1=1.5. Viewer is in air n2=1.00. Radius of surface is r = infinity.  1/s’ = -0.15  s’ = -6.67cm..

17. 17 OI

18. 18 Question: Reverse the designations in the example above. Object is now the fish, so n1 = 1.33 (fish location). Let the fish be 10cm from bowl surface. Where is the image of the fish formed that the cat will see? Answer: s = 10cm, s’ = ?, r = -15cm, n1 = 1.33, n2 = 1.00.  0.133 + 1/s’ = 0.022  1/s’ = -0.111  s’ = -9.00cm

19. 19 Calculating Focal Length for a Thin Lens Example: A double convex, thin glass lens with n = 1.5 has radii of curvature of 10 and 15cm. Find its focal length.

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22. 22 s, cat’s nose n1 holds object, here equal to 1.00 0.1 +1.33/s’= 0.022 1.33/s’ = -0.078 s’ = -17.1cm

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