2. The spoon is separated into 2 parts Something different for light travel in water !!! P.51

4. Light Travels with different speeds in different media Vacuum : c = 3x10 8 ms -1 (fastest) Light travels slower in air, water or glass P.51

6. Light travels from 1 medium to another obliquely Speed of light changesDirection of light ray changes (bending) Refraction P.51

8. Track Glass P.51

9. Speed of light in air = 3x10 8 ms -1 Speed of light in water = 2.25x10 8 ms -1 Light ray bends towards normal P.51

10. Speed of light in glass = 2x10 8 ms -1 Light ray bends away from normal Speed of light in water = 2.25x10 8 ms -1 P.51

11. Track Glass P.51

12. Speed of light in air = 3x10 8 ms -1 Speed of light in water = 2.25x10 8 ms -1 Light ray travels straight at normal incidence P.51

13. Glass P.51

14. Glass Water P.51

15. Water P.51

16. P.51 Q1

17. Medium 1 Medium 2 11 22 P.52

18. Laws of refraction 1 n 2 depends on medium 1 & 2 Incident ray, refracted ray & normal lie in the same plane P.52

19. 0o0o Medium 1 : air Medium 2 : glass P.52

20. sin  1 sin  2 1 1 11 0o0o 15 o 30 o 45 o 60 o 75 o 22 sin  1 sin  2 11 0o0o 15 o 30 o 45 o 60 o 75 o 22 0o0o 9.9 o 19.5 o 28.1 o 35.3 o 40 o sin  1 sin  2 11 0o0o 15 o 30 o 45 o 60 o 75 o 22 0o0o 9.9 o 19.5 o 28.1 o 35.3 o 40 o sin  1 00.2590.50.7070.8660.966 sin  2 11 0o0o 15 o 30 o 45 o 60 o 75 o 22 0o0o 9.9 o 19.5 o 28.1 o 35.3 o 40 o sin  1 00.2590.50.7070.8660.966 sin  2 00.1730.3330.4710.5770.644 P.52

21. Medium 1 : vacuum (air) Medium 2 : substance X Refractive index Absolute refractive index P.52

22. Medium 1 : air Medium 2 : waterMedium 2 : glass P.52

23. Refractive index > 1 Light ray bends towards normal2 nd medium is optically denserLight ray travels slower in 2 nd medium If refractive index is larger, light ray bends towards normal in a larger extent P.52

24. Medium 1 : air Medium 2 : Y P.52

25. Refractive index < 1 Light ray bends away from normal2 nd medium is optically less denseLight ray travels faster in 2 nd medium If refractive index is smaller, light ray bends away from normal in a larger extent P.52

26. Refraction Medium 1 : air (vacuum) Change of speed P.52

27. n w = 1.33 c = 3x10 8 ms -1 n g = 1.5 wngwng gnwgnw P.52

28. Medium 1 Medium 2 P.52

29. n air = 1n water = 1.33n glass = 1.5 water n glassglass n water water n air P.52

30. Generalised Snell’s law True for light travelled from medium 1 to medium 2 or from medium 2 to medium 1 P.52

31. Water (n w =1.33) Glass (n g = 1.5) 60 o P.52

32. X (n X =1.8) Y (n Y = 1.4) 40 o P.52

33. Water (n w =1.33) Air (n air = 1) 30 o P.52

34. Refractive index of water = 1.33  a = 45 o  a = 60 o  w = 30 o P.52

35. n glass = 1.5  a = 45 o n Y = 0.8  a = 45 o P.52

36. 45 o air n water = 1.33 n glass = 1.5 X n Y = 1.2 40 o P.52

37. Q.1 slope = 1/0.64 = 1.56 Q.2(a) n = sin 60 o / sin 21 o n = 2.416 Q.2(b) n = sin 60 o / sin 41 o n = 1.32 Q.3(a) n = 1.33 for water n = sin 45 o / sin θ w sin θ w = sin 45 o / n θ w = 32.1 o P.53

38. Glass Mirror P.53 Q4

39. P.54 Q5

40. P.54 Exercise Q.6 sin θ r = sin 30 o / 1.33 θ r = 22.1 o Q.7n = sin 20 o / sin θ r (1/1.5) = sin 20 o / sin θ r θ r = 30.9 o

41. Medium 1 Medium 2 60 o 22 =30 o n=sin 60 o / sin 30 o n=1.73 P.54 Q8

42. Water (n w =1.33) Glass (n g = 1.5) 60 o 22 D Angle of deviation Direction of travel changes P.54

43. Water (n w =1.33) Air (n air = 1) 30 o 22 D Angle of deviation is the difference between i and r P.54

44. Lateral displacement P.55

45. Air Glass n g = 1.5 45 o 22 33 44 dd 3cm D x P.55

46. P.5 Q1 P.55 X Bends away from normal X X Bends towards normal in 2 nd path Correct

47. P.55 Q2 n Violet > n Red bending Violet > bending Red X Bends away from normal X X X Correct

48. Glass n g =1.5 60 o 50 o 22 33 44 D P.56

49. Q.3(a) n = sin 30 o / sin 19 o n = 1.536 Q.2(b)(i)Decrease Q.2(b)(ii)Increase Q.2(b)(iii)Increase Q.2(d)Periscopes, Binoculars P.56

53. 60 o 50 o 44 D  2 (red) = 31.77 o  2 (violet) = 31.24 o Find refractive indices for red & violet light Find angle of deviation of red light Compare speed of red & violet light in glass P.56

54. Observation White light consists of 7 different coloursRed, orange, yellow, green, blue, indigo and violet Red light has a smaller refractive index Red light travels faster in glass P.56

55. Spectrum P.56

60. Refraction Depth of image of coin is smaller P.56

61. I

62. Dipped rod appears to bend at the surface of water P.56

63. I

64. Lines appear raised under the glass P.56

65. P.57

66. Real depth Apparent depth Image & object have same size Apparent depth < real depth if light ray bends away from normal P.57

67. O I 40cm a.d. aa 5o5o x If  is small, sin   tan  n a = 1 P.57

68. P.58 Q1 Cannot see the coin

69. P.58 Q1 Cannot see the coin

70. P.58 Q1 Can see the coin

71. n g = 1.5 3 cm Find the apparent depth P.58 a.d. = 3 / n g = 3/1.5 = 2 (cm)

72. Find the distance between the image of the boy & the fish 4 m 3 m Find the distance between the image of the fish & the boy P.58

73. 4 m 3 m Find the distance between the image of the fish & the boy P.58 a.d. fish = 3 / n w = 3/1.33 = 2.26 (m) 2.26 m Distance = 4 +2.26 = 6.26(m)

74. 4 m 3 m Find the distance between the image of the boy & the fish P.58 a.d. boy = 4 / (1/n w )= 4*1.33 = 5.32 (m) 5.32 m Distance = 3 +5.32 = 8.32(m)