2. Thin Lenses

3. 91 is the highest grade while 75 is the lowest grade. 91 is the highest grade while 75 is the lowest grade. Best Project ( Website and Reflection Paper).......all Best Project ( Website and Reflection Paper).......all Best Portfolio...... Best Portfolio......

4. Lecture fom Mirror From what material are curve mirrors made from? From what material are curve mirrors made from? How plane and curve mirrors formed images? How plane and curve mirrors formed images? What are the types of curved mirrors? What are the types of curved mirrors? State the mirror and magnification equation use to locate an image in curved mirrors. State the mirror and magnification equation use to locate an image in curved mirrors.

5. What is prism?

6. Light going through a prism bends toward the base n 1 n 2 n =1 1 Bending angle depends on value of n 2 n 1

9. Refraction in Prisms Two prisms base to base If we apply the laws of refraction to two prisms, the rays bend toward the base, converging light. Parallel rays, however, do not converge to a focus leaving images distorted and unclear.

10. Refraction in Prisms (Cont.) Two prisms apex to apex Similarly, inverted prisms cause parallel light rays to bend toward the base (away from the center). Again there is no clear virtual focus, and once again, images are distorted and unclear.

11. Lenses? Lenses?

12. What is a lens? A transparent object that refracts light rays, causing them to converge or diverge to create an image A transparent object that refracts light rays, causing them to converge or diverge to create an image

13. Types of Converging Lenses In order for a lens to converge light it must be thicker near the midpoint to allow more bending. Double-convex lens Plano-convex lens Converging meniscus lens

14. Types of Diverging Lenses In order for a lens to diverge light it must be thinner near the midpoint to allow more bending. Double-concave lens Plano-concave lens diverging meniscus lens

15. Converging Lenses A converging lens is thicker at the middle than it is at the rim A converging lens is thicker at the middle than it is at the rim –The front of the lens is the side of the lens where the object is Converging lenses can produce real or virtual images Converging lenses can produce real or virtual images

16. Converging Lenses The focal points are equidistant from the center of the lens. That distance is the focal length of the lens. FF2 F

17. Converging Lens Reference Rays Ray From object to lens From lens to image Parallel Ray Parallel to principal axis Passes through focal point F Central Ray To the center of the lens From the center of the lens Focal ray Passes through focal point F Parallel to principal axis

18. Converging Lenses The focal points are equidistant from the center of the lens. That distance is the focal length of the lens. FF2 F Ray 1 Ray 2 Ray 3

19. Images Created by Converging Lenses

20. Images produced by lenses An object infinitely far away from a converging lens will create a point image at the focal point An object infinitely far away from a converging lens will create a point image at the focal point –i.e. light from the Sun

21. Images produced by lenses As a distant object approaches the focal point, the image becomes larger and farther away As a distant object approaches the focal point, the image becomes larger and farther away

22. Images produced by lenses When the object is at the focal point, the light rays exit parallel to each other and the image is “at infinity” When the object is at the focal point, the light rays exit parallel to each other and the image is “at infinity” –i.e. a lighthouse or a searchlight

23. Images produced by lenses When the object is inside the focal point, the rays are drawn the same way but you must extend them backwards in order to find the image When the object is inside the focal point, the rays are drawn the same way but you must extend them backwards in order to find the image

24. Converging Lens: Objects inside the focal point FF2 F These rays are diverging and won’t cross Draw lines extending backwards to form the image

25. Summary Object position Image Position Real or virtual Magnified or diminished Inverted or erect >2F at 2F between 2F and F at F between F and lens between F and 2F at 2F > 2F at infinity same side as object virtual real magnified same size diminished upright inverted

26. DivergingConverging 2. Locate and describe the image below

27. Seatwork 1 (Lecture Note) 1. 1. A converging lens has a focal length of 17 cm. A candle is located 48 cm from the lens. What type of image will be formed, and where will it be located? 2. A plano-convex lens of focal length 5.0 cm is used in reading lamp to focus light from a bulb on a book. If the lens is 60.0 cm from the book, how far should it be from bulb’s filaments? 3. A toy of height 8.4 cm is balanced in front of a converging lens. An inverted, real image of height 23 cm is noticed on the other side of the lens. What is the magnification of the lens?

28. 27 The focal length of particular lens depends both on the index of refraction n of its material relative to that of the medium it is in and on the radii of curvature R 1 and R 2. 1/f = (n-1) ( 1/R1 + 1/R2) R is + if the surface is convex. R is – if the surface is concave. f is + for converging lens f is negative for diverging lens It does not matter which surface is considered as1 and 2.

29. A meniscus lens has a convex surface whoe radius of curvature is 25 cm and a concave surface whose radius of curvature is 15 cm. The index of rafraction is 1.52. Find the focal length of the lens and wether it is converging or diverging. A meniscus lens has a convex surface whoe radius of curvature is 25 cm and a concave surface whose radius of curvature is 15 cm. The index of rafraction is 1.52. Find the focal length of the lens and wether it is converging or diverging.

30. Thin Lens and Magnification Equations

31. Sign conventions for lenses + p Object distance for lenses q Image in back of the lens ( real) Image in front of the lens (virtual) f Converging Lens Diverging Lens

32. Sample Problem Sherlock Holmes examines a clue by holding his magnifying glass (with a focal length of 15.0 cm) 10.cm away from an object. Find the image distance and the magnification. Describe the image he observes. Draw a ray diagram to confirm your answers. Sherlock Holmes examines a clue by holding his magnifying glass (with a focal length of 15.0 cm) 10.cm away from an object. Find the image distance and the magnification. Describe the image he observes. Draw a ray diagram to confirm your answers.

33. What kind of lens is a magnifying glass? Magnifying glasses produce enlarged images. Therefore, a magnifying glass is a converging lens. Magnifying glasses produce enlarged images. Therefore, a magnifying glass is a converging lens. f = + 15 cm, p= +10 cm f = + 15 cm, p= +10 cm

34. Solve the problem The image is virtual and upright

35. Magnifying Lens Ray Diagram FF2 F Object Notice that the image is located at 2F (30 cm) and it is also in front of the lens which is why q is negative.

36. Diverging Lenses A diverging lens is thinner at the middle than it is at the rim A diverging lens is thinner at the middle than it is at the rim A diverging lens has two focal points but only one focal length A diverging lens has two focal points but only one focal length Diverging lenses only produce virtual images Diverging lenses only produce virtual images

37. Diverging Lenses The focal points are equidistant from the center of the lens. That distance is the focal length of the lens. FF2 F

38. Diverging Lens Reference Rays Ray From object to lens From lens to image Parallel Ray Parallel to principal axis Directed away from focal point F Central Ray To the center of the lens From the center of the lens Focal ray Proceeding toward back focal point, F Parallel to principal axis

39. Drawing the Rays FF2 F Ray 1 Ray 2 Ray 3

40. Sample Problem (p.579 #1) Using a ray diagram, find the position and height of an image produced by a viewfinder in a camera with a focal length of 5.0 cm if the object is 1.0 cm tall and 10.0 cm in front of the lens. A camera viewfinder is a diverging lens. Using a ray diagram, find the position and height of an image produced by a viewfinder in a camera with a focal length of 5.0 cm if the object is 1.0 cm tall and 10.0 cm in front of the lens. A camera viewfinder is a diverging lens.

41. Ray Diagram FF2 F Object The image is about 1/3 of the object height (.33 cm). The image location is about 3 or 4 cm from the lens. So, q is approximately -3.5 cm.

42. Smart people verify!

43. Group 1 Human Eyes a. Identify and describe the parts of the human eye vital in seeing objects. b. Describe how image is formed in the retina ( Ray diagram is needed). c. Explain how the eye accommodates to see clearly both far and near objects.

44. Group 2 Camera a. Identify and describe the parts of the camera. b. Describe how image is formed in the camera (Ray diagram is needed) c. Similarities and differences of the camera and the human eye.

45. Group 3 Vision Defects a. a.Myopia and its Causes and corrective lens (w/ ray diagrams) b. Hyperopia eyes and its Causes and corrective lens (w/ ray diagrams) c. c.Presbyopia eyes and its Causes and corrective lens (w/ ray diagrams) d. d.Astigmatism eyes its causes and corrective lens (w/ ray diagrams)

46. Group 4 Microscope a.Parts of the microscope and its function. b.Image formation in objective and eyepiece lens w/ ray diagrams

47. Group 5 Telescope a.Parts of the telescope and its function. b.Image formation in objective and eyepiece lens w/ ray diagrams

48. Group 6 Different Optical Instrument Picture and its uses / function/s a.Periscope b.Endoscope c.Interferometer d.Spectrometer e.Sunglasses