Reflection of Light in Mirrors - Science 10 (S10FE-IIg-h-50-52)

Lesson 1: Reflection of Light in Plane Mirrors
Lesson 2: Reflection of Light in Spherical Mirrors
Lesson 3: Optical Instruments (Camera, Microscope, Telescope)

Reference:
DepEd K12. (2019, July). Science Grade 10 Learner’s Materials. [PDF File]. Retrieved from https://www.depedk12.com/2019/07/science-grade-10-learners-materials-pdf.html

1. science 10 – week 3

2. UNIT 1 REFLECTION OF LIGHT IN MIRRORS

3. unit map

4. Before you start with our lesson, answer first the pre-assessment on the ASSESSMENT SHEETS.

5. lesson 1: REFLECTION OF LIGHT IN PLANE MIRRORS

6. Objectives : In this lesson, you are expected to: 1. differentiate real and virtual image; and 2. compare the actual size and the distance from the mirror of the object with that of the image formed by plane mirror.

7. Reflection of Light Reflection is the bouncing off of light rays when it hits a surface like a plane mirror. Real Image – formed in front of the mirror and is always upside down relative to the object. It can be projected on a screen placed in front of mirror. Virtual Image – formed behind the mirror and is upright relative to the object and cannot be projected on a screen.

8. Reflection The change in direction of a wave when it strikes and rebounds from a surface or the boundary between two media Reflection can be thought of as light “bouncing off” a surface (although this phenomena is much more complex). Regular (specular) reflection – reflection from very smooth (mirror) surfaces Irregular (diffuse) reflection – reflection from relatively rough surfaces

9. Specular & Diffuse Reflection

10. Law of Reflection The angle of reflection q r is equal to the angle of incidence q i . The reflected and incident rays are also in the same plane.

11. Reflection of Light in Plane Mirrors Images formed by plane mirrors are always virtual, upright, the same size as the object, the same distance behind the mirror as the object is in front of the mirror, and laterally reversed. Laterally reversed means that left of the object becomes the right of the image, and vice versa.

12. Reflection of Light in Plane Mirrors Suppose that a girl, with a sitting height of 3ft, is facing 2 ft away from a plane mirror as she puts blush-on on her right cheek. Describe the image formed by each mirror.

13. Reflection of Light in Plane Mirrors Explanation: We are given that the girl is 2ft away from the mirror. Recall that images formed by plane mirrors are always virtual, upright, the same size as the object, the same distance behind the mirror as the object is in front of the mirror, and laterally reversed. So the girl will see her image in mirror that is 2ft at its back, meaning it is virtual. It is sitting at the same size of 3.5ft height and the image will tell us that she is putting blush-on on her left cheek.

14. learn more! To learn more about our lesson, open the file Reflection of Light and Image Formation in your flash drive or access this link: http://www.physicsclassroom.com/class/refln/Lesson-3/Reflection-of-Light-and-Image-Formation

15. quiz time! Let’s check your understanding of our lesson. Answer Activity 2-3 on the ASSESSMENT SHEETS.

16. lesson 1: REFLECTION OF LIGHT IN PLANE MIRRORS

17. science 10 – week 3

18. UNIT 1 REFLECTION OF LIGHT IN MIRRORS

19. unit map

20. lesson 2: REFLECTION OF LIGHT IN curved MIRRORS

21. Objectives : In this lesson, you are expected to: 1. describe the location, size, and orientation of the images formed by curved mirrors; and 2. construct ray diagrams to determine the location, orientation, size, and type of images formed by curved mirror.

22. key terms Center of Curvature, C - the center of the sphere of which the mirror is part. Its distance from the mirror is known as the radius. Vertex, V - the center of the mirror. Focal Point/ Focus, F - the point between the center of the curvature and vertex. Its distance from the mirror is known as the focal length, f. Principal Axis – the point where the reflected rays meet (concave) or where they seem to come from (convex).

23. types of curved mirrors a. Convex mirrors – the image formed by convex mirror is never real because the reflected rays spread out from the mirror. Images formed by convex mirror are always found between F and V, virtual, upright, and smaller than the object. Example: side mirror and security mirrors that provide wider range of view for the driver by making images smaller and closer than they appear.

24. types of curved mirrors b. Concave mirrors – a concave mirror can produce real or virtual images, depending on the distance between the mirror and the object. The image may also be larger than, the same size as, or smaller than the object. Example: dental mirrors for the dentist to view an enlarged virtual image of the teeth.

25. the four principal rays Images formed in a curved mirror can be located and described through ray diagramming. The P – F ray, F – P ray, C – C ray, and the V ray are the ‘Four Principal Rays’ in curve mirrors.

26. the four principal rays 1. P – F Ray. A ray of light parallel to the principal axis is reflected passing through the principal focus, F.

27. the four principal rays 1. P – F Ray. A ray of light parallel to the principal axis is reflected as if passing through the principal focus, F.

28. the four principal rays 2. F – P Ray. A ray of light passing through the focus, F is reflected parallel to the principal axis.

29. the four principal rays 2. F – P Ray. A ray of light directed towards the focus, F is reflected parallel to the principal axis.

30. the four principal rays 3. C – C Ray. A ray of light passing through the center of curvature, C reflects back along its own path.

31. the four principal rays 3. C – C Ray. A ray of light directed towards the center of curvature, C reflects back along its own path.

32. the four principal rays 4. V Ray. A ray of light directed to the vertex reflects at equal angle from the principal axis.

33. the four principal rays 4. V Ray. A ray of light directed to the vertex reflects at equal angle from the principal axis.

34. steps in determining the position and nature of image formed in curved mirrors 1. From the object, draw the first ray (P – F ray).

35. steps in determining the position and nature of image formed in curved mirrors 2. From the same point on the object, draw the second (F – P ray).

36. steps in determining the position and nature of image formed in curved mirrors 3. Third (C – C ray).

37. steps in determining the position and nature of image formed in curved mirrors 4. Fourth (V ray) rays.

38. steps in determining the position and nature of image formed in curved mirrors

39. steps in determining the position and nature of image formed in curved mirrors

40. images formed in concave mirrors Location of the Object Image Location Orientation Size Type Very far (at infinity) At F inverted very small, almost a point real Beyond C Between C and F inverted smaller than the object real At C At C inverted same size as the object real Between C and F Beyond C inverted bigger than the object real At F At infinity No image formed because all reflected rays are parallel Between F and V Back of the mirror upright bigger than the object virtual

41. learn more! To learn about our lesson open the file Mirror Therapy on your flash drive or visit the link http://www.physiopedia.com/Mirror_Therapy

42. quiz time! Let’s check your understanding of our lesson. Answer Activity 4 on the ASSESSMENT SHEETS.

43. lesson 2: REFLECTION OF LIGHT IN curved MIRRORS

44. science 10 – week 3

45. UNIT 1 REFLECTION OF LIGHT IN MIRRORS

46. unit map

47. lesson 3: optical instruments

48. Objective : In this lesson, you are expected to: 1. explain how different optical instruments work.

49. camera It is the man’s answer to the eye’s inability to produce a permanent record of the image formed at the retina. Roger Bacon, an English philosopher and scientist, was believed to have invented the instrument in 1267. In 1826, Joseph- Nicéphore Niépce , a French scientist and inventor, created the first photographic camera that has a lens to project an image onto light-sensitive paper.

50. conventional camera It uses film in storing images. A 35mm conventional camera can take only up to 36 exposures. One has to rewind the film, open the back, and replace film with another if more pictures are to be taken. The film will have to be developed and the negatives printed before seeing the pictures.

51. digital camera It uses digital sensor array made of millions of tiny sensor points called pixels, which is short for “picture elements”, that convert light into electrical charges. They are laid out in an array with rows and columns. For instance, a camera with 3000 pixels horizontally and 1000 pixels vertically has 3000 x 1000 pixels equal to 3 million pixels. Thus, it is called 3 Megapixels camera. Digital camera is provided with video monitor for instant viewing of each picture taken.

52. magnifier and microscope To examine an object, we hold it as near as possible to our eye so that bigger image can be viewed, however, if an object is placed shorter than 25-cm from the eye, blurred image is produced. Magnifying glasses and microscopes produce a virtual, upright and enlarged image of an object.

53. telescope A device that enables us to see distant objects. The first image formed at principal focus of objective is real, inverted and smaller. Then the eyepiece, acting like a magnifying glass produces a magnified virtual final image at infinity. A zoom lens is also telescope mounted on a camera while a binocular is simply two telescope mounted side by side.

54. learn more! To learn about our lesson open the file Digital Camera or visit the link http://electronics.howstuffworks.com/cameras-photography/digital/digital-camera2.htm

55. Let’s check your understanding of our lesson. Answer Activity 5 on the ASSESSMENT SHEETS.

56. values integration Have you heard the Golden Rule of Life: “Do unto others what you want others do unto you”? How does this line related to what you had learned in studying plane mirrors? Do you believe that what you do in life will reflect back to you also? Use the same situations that we are experiencing or witnessing right now in supporting your answers.

57. “There is a spiritual mirror that we can look into that will show us who we are. That mirror is called THE WORD OF GOD” James 1:22-25

58. lesson 3: optical instruments