1. 1.Describe two differences between electromagnetic waves and other (mechanical) waves. 2.Write down the names of all seven types of electromagnetic waves in order of increasing frequency. 3.The wavelength of microwave radiation produced by a microwave oven is 12.2 cm. Calculate the corresponding frequency.

2. Curved Mirrors, Ray Diagrams and Nature of Image

3. Question: How do we “see” things?

7. Mirror Normal

8. ? Mirror Brick Wall Mr. X ABCD

9. Plane Mirrors Light from object reflects into eye Eye sees image back here Image is virtual and laterally inverted

10. ATOYOT

11. The two types of curved mirrors: 1.Concave (Converging) Mirror 2.Convex (Diverging) Mirror

12. Concave (Converging) Mirrors

13. Concave (Converging) Mirrors

22. Concave Mirrors Concave (or converging) mirrors focus light at the focal point. F

23. Convex (Diverging) Mirrors

29. Convex Mirrors Convex mirrors have a focal point behind the mirror. Convex (or diverging) mirrors spread the light rays apart so that they appear to have come from the focal point F

30. Ray Diagrams

31. P = pole, pa = principal axis C = centre of curvaturer = radius of curvature F = Focal point or focusf = focal length f = r / 2 C F P r pa f

32. The two important rules: 1.Parallel to pa → Focal point 2.Focal point → Parallel to pa (pa = principal axis, the horizontal line)

37. Concave (Converging) Mirror SizeOrientationNature Behind C At C Between C & F At F Between F & P

41. 1.2.3. 4.5.

42. Concave (Converging) Mirror SizeOrientationNature Behind C DiminishedInvertedReal At C SameInvertedReal Between C & F EnlargedInvertedReal At F No image Between F & P EnlargedUprightVirtual

47. Concave (converging) mirrors The image will be real and inverted if the object is located behind the principal focus. The image will be virtual, upright and enlarged if the object is located between the mirror and the principal focus. Convex (diverging) mirrors Convex mirrors always produce virtual images which are always upright and smaller than the object. The image is formed behind the mirror, between the principal focus and the mirror.

48. Mirror Formulae ONE Descartes’ Formula: and: m = magnification factor h = height d = distance from mirror

49. f is + if the mirror is concave f is − if the mirror is convex d i is + if the image is in front of the mirror d i is − if the image is behind the mirror h i is + if the image is upright/virtual h i is − if the image is inverted/real m > 1 if the image is enlarged

50. Using Descartes’ Formula – EXAMPLES a)Find the position of the image of an object located 40m in front of a concave mirror of radius of curvature 64m. b)An object 7m high is placed 15m from a convex mirror of radius 45m. Find the position AND the height of the image.

51. Newton’s Formula: and: S = distance from focal point All distances are positive but care must be taken when calculating S i or S o Mirror Formulae TWO

52. Using Newton’s Formula – EXAMPLES a)An object 7m high is placed 15m from a convex mirror of radius 45m. Find the position AND the height of the image. b)An object 6m high is placed 30m in front of a convex mirror of focal length 40m. Find the position, nature and size of the image formed.

53. Finish these by this Thursday 1.Homework Booklet Worksheet TWO 2.Activity 5B