1. Chapter 32Light: Reflection and Refraction

2. 32-3 Formation of Images by Spherical Mirrors Example 32-7: Convex rearview mirror. An external rearview car mirror is convex with a radius of curvature of 16.0 m. Determine the location of the image and its magnification for an object 10.0 m from the mirror.

3. Magnification: Magnification = image height / object height = - image distance (d i ) / object distance (d 0 ) d0d0 didi m and h i are negative if the image is upside down. d i is negative if the image is virtual

4. Magnification: Magnification = image height / object height = - image distance (d i ) / object distance (d 0 ) dodo Negative m = upside down Negative d i = virtual (behind mirror) -di d0d0 didi

5. Problem 26 26.(II) A shaving or makeup mirror is designed to magnify your face by a factor of 1.35 when your face is placed 20.0 cm in front of it. (a) What type of mirror is it? (b) Describe the type of image that it makes of your face. (c) Calculate the required radius of curvature for the mirror.

6. We use ray diagrams to determine where an image will be. For mirrors, we use three key rays, all of which begin on the object: 1.A ray parallel to the axis; after reflection it passes through the focal point. 2.A ray through the focal point; after reflection it is parallel to the axis. 3.A ray perpendicular to the mirror; it reflects back on itself. 32-3 Formation of Images by Spherical Mirrors

7. Mirror Equation Sign Conventions for Mirrors Quantity Positive “ + ”Negative “ - ” Object distance d 0 RealVirtual Image distance, d i RealVirtual Focal length, f Concave: f=r/2Convex: f=-r/2 Magnification, m UprightUpside down f≠d0+dif≠d0+di

8. In general, light slows somewhat when traveling through a medium. The index of refraction of the medium is the ratio of the speed of light in vacuum to the speed of light in the medium: 32-4 Index of Refraction

9. Light changes direction when crossing a boundary from one medium to another. This is called refraction, and the angle the outgoing ray makes with the normal is called the angle of refraction. 32-5 Refraction: Snell’s Law

10. Refraction is what makes objects half-submerged in water look odd. 32-5 Refraction: Snell’s Law

11. The angle of refraction depends on the indices of refraction, and is given by Snell’s law: 32-5 Refraction: Snell’s Law

12. Example 32-8: Refraction through flat glass. Light traveling in air strikes a flat piece of uniformly thick glass at an incident angle of 60, as shown. If the index of refraction of the glass is 1.50, (a) what is the angle of refraction θ A in the glass; (b) what is the angle θ B at which the ray emerges from the glass?

13. Problem 43 43.(II) A light beam strikes a 2.0-cm-thick piece of plastic with a refractive index of 1.62 at a 45° angle. The plastic is on top of a 3.0-cm-thick piece of glass for which What is the distance D in Fig. 32–48?

14. 32-6 Visible Spectrum and Dispersion The visible spectrum contains the full range of wavelengths of light that are visible to the human eye.

15. 32-6 Visible Spectrum and Dispersion This spreading of light into the full spectrum is called dispersion. If Light goes from air to a certain medium:

16. If light passes into a medium with a smaller index of refraction, the angle of refraction is larger. There is an angle of incidence for which the angle of refraction will be 90°; this is called the critical angle: 32-7 Total Internal Reflection;

17. If the angle of incidence is larger than the critical angle, no refraction occurs. This is called total internal reflection. 32-7 Total Internal Reflection; Fiber Optics

18. Conceptual Example 32-11: View up from under water. Describe what a person would see who looked up at the world from beneath the perfectly smooth surface of a lake or swimming pool.

19. Chapter 33 Lenses and Optical Instruments

20. Thin lenses are those whose thickness is small compared to their radius of curvature. They may be either converging (a) or diverging (b). 33-1 Thin Lenses; Ray Tracing

21. Thin Lenses Converging Diverging Thickest in the center Thickest on the edges

22. Parallel rays are brought to a focus by a converging lens (one that is thicker in the center than it is at the edge). 33-1 Thin Lenses; Ray Tracing

23. A diverging lens (thicker at the edge than in the center) makes parallel light diverge; the focal point is that point where the diverging rays would converge if projected back. 33-1 Thin Lenses; Ray Tracing

24. The power of a lens is the inverse of its focal length: Lens power is measured in diopters, D: 1 D = 1 m -1. 33-1 Thin Lenses; Ray Tracing

25. Ray tracing for thin lenses is similar to that for mirrors. We have three key rays: 1.The ray that comes in parallel to the axis and exits through the focal point. 2.The ray that comes in through the focal point and exits parallel to the axis. 3.The ray that goes through the center of the lens and is undeflected. 33-1 Thin Lenses; Ray Tracing

26. Thin Lenses: Converging Principle axis 1.Parallel ray goes through f 2.Ray through center 3.Ray through f comes out parallel f object image Image: Upright or upside down Real or virtual Bigger or smaller f Focal point is on both sides of the lens equidistant from the lens

27. Thin Lenses: Diverging 1.Parallel ray goes through f 2.Ray through center is straight 3.Ray through f comes out parallel fobjectimage Upright or upside down Real or virtual Bigger or smaller Image: f For lenses virtual images are formed in front of the lens f

28. The sign conventions are slightly different: 1.The focal length is positive for converging lenses and negative for diverging. 2.The object distance is positive when the object is on the same side as the light entering the lens (not an issue except in compound systems); otherwise it is negative. 3.The image distance is positive if the image is on the opposite side from the light entering the lens; otherwise it is negative. 4.The height of the image is positive if the image is upright and negative otherwise. 33-2 The Thin Lens Equation; Magnification

29. 33-2 Magnification: Magnification = image height / object height = - image distance (d i ) / object distance (d 0 ) d0d0 -d i didi d0d0 Negative m = upside down Negative d i =virtual

30. Lens Equation Sign Conventions for lenses and mirrors Quantity Positive “ + ”Negative “ - ” Object distance d 0 Real*Virtual* Image distance, d i Real and behind the lens Virtual and same side as object Focal length, f ConvergingDiverging Magnification, m UprightUpside down