1. Optics
The Study of Light

2. Areas of Optics Geometric Optics Light as a ray. Physical Optics
Light as a wave.
Quantum Optics
Light as a particle.

3. Optical images Nature Orientation Size real (converging rays)
virtual (diverging rays)
Orientation
upright
inverted
Size
true
enlarged
reduced

4. Law of Reflection
Angle of incidence equals angle of reflection. r i

5. Plane Mirror + -
Image
-5 cm
object
5 cm

6. Spherical mirrors shiny shiny concave convex + - + -
(where reflected rays go)
(dark side)
(where reflected rays go)
(dark side)
concave
convex
Focal length, f, is positive
Focal length, f, is negative

7. Parts of a Spherical Concave Mirror+ -
Vertex
Center
Focus
Principle axis

8. Spherical Concave Mirror (object outside center)F
Real, Inverted, Reduced Image f

9. Spherical Concave Mirror (object at center)F
Real, Inverted, True Image

10. Spherical Concave Mirror (object between center and focus)
Real, Inverted, EnlargedImage

11. Spherical Concave Mirror (object at focus)
No image

12. Spherical Concave Mirror (object inside focus)
Virtual, Upright, Enlarged Image

13. Parts of a Spherical Convex Mirror+ -
Principle axis
Focus
Center

14. Spherical Convex MirrorF C
Virtual, Upright, Reduced Image

15. Mirror equation #1 1/si + 1/so = 1/f si: image distance
so: object distance
f: focal length

16. Mirror equation # 2 M = -si/so = hi/ho si: image distance
so: object distance
hi: image height
ho: object height
M: magnification

17. Concave vs convex mirrors
Image is real when object is outside focus
Image is virtual when object is inside focus
Focal length f is positive
Convex
Image is always virtual
Focal length f is negative

18. Real vs Virtual images Real Virtual Formed by converging light rays
si is positive when calculated with mirror equation
Virtual
Formed by diverging light rays
si is negative when calculated with mirror equation

19. Upright vs Inverted images
Always virtual if formed by one mirror or lens
hi is positive when calculated with mirror/lens equation
Inverted
Always real if formed by one mirror or lens
hi is negative when calculated with mirror/lens equation

20. Definition: Refraction
Change in speed of light as it moves from one medium to another.
Can cause bending of the light at the interface between media.

21. n = c/v n = Index of Refraction speed of light in vacuum
speed of light in medium
n = c/v
n =

22. Snell’s Law n1sin 1 = n2sin 2 n1 n2 1 2 angle of incidence
angle of refraction

23. n1 < n2
light bends toward normal 1 n1 n2 2

24. n1 > n2
light bends away from normal 1 n1 2 n2

25. Dispersion
The separation of white light into colors due to different refractive indices for different wavelengths.

26. Dispersion
Due to different indices of refraction for different wavelengths of light.

27. Critical Angle of Incidence
Light would refract 90o so it reflects instead, undergoing total internal reflection. r n2
n1 > n2

28. Calculating Critical Angle
n1sin(1) = n2sin(2)
n1sin(90o) = n2sin(2)
n1 = n2sin(c)

29. Total Internal Reflection
Occurs only when angle of incidence > critical angle n2

30. Announcements 4/16/2017
Turn in homework (lens problems) on overhead.
Lab report will be due next week (on looseleaf or graph paper).

31. Consider a lens with f = 20 cm.
You place a 5 cm tall object 30 cm in front of the lens.
Draw the ray diagram and construct the image.
Calculate the image distance and height using the lens/mirror equations.
Name the image.

32. Converging lens #1 + - 2F F C F 2F
Real, Inverted, Reduced Image

33. Converging lens #2 + - 2F F C F 2F
Real, Inverted, True Image

34. Converging lens #3 + - 2F F C F
Real, Inverted, Enlarged Image

35. Converging lens #4 + - F C F
Virtual, Upright, Enlarged Image

36. For converging lenses f is positive so is positive
si is positive for real images and negative for virtual images
M is negative for real images and positive for virtual images
hi is negative for real images and positive for virtual images

37. Diverging lens + - F C F
Virtual, Upright, Reduced Image

38. For diverging lenses f is negative so is positive si is negative
M is positive and < 1
hi is positive and < ho