UNIT D Review

Key Terms Review1. Create a mind map using the following terms.

You may add more terms if you wish.

• angle of incidence

• angle of reflection

• angle of refraction

• camera

• concave mirror

• converging lens

• convex mirror

• diverging lens

• focal point

• luminescence

• magnification

• microscope

• mirage

• telescope

• virtual image

2. In a short paragraph, describe properties oflight. You may wish to use some of the termsfrom question 1.

Light is part of the electromagneticspectrum and travels in waves.

3. (a) Draw a sketch of the electromagneticspectrum.

(b) Label the different types ofelectromagnetic radiation.

4. What is the difference betweenelectromagnetic radiation and theelectromagnetic spectrum?

5. (a) What is the amplitude of the wave below?

(b) What is the wavelength of the wavebelow?

(c) Copy the wave into your notebook andlabel amplitude, wavelength, crest, trough,and resting position.

6. What is the relationship between wavelengthand frequency?

7. List the colours of the visible spectrum, fromlowest to highest energy.

8. (a) What are the three primary colours oflight?

(b) What are the three secondary colours of light?

(c) Describe how each secondary colour oflight is produced.

9. In terms of subtractive colour theory, explainwhy a darker coloured object will heat upfaster than a lighter coloured object.

10. What colour of light would you observe if youcombined equally bright lights of the threeprimary colours?

11. (a) Name seven different sources of light.

(b) Give an example of each source.

12. State how fluorescence and phosphorescenceare:

(a) similar

(b) different k

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ACHIEVEMENT CHART CATEGORIES

Knowledge and understanding Thinking and investigation

Communication Applicationac

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13. What assumption does the ray model of lightmake about how light travels?

14. (a) List three terms that describe how lightinteracts with various materials.

(b) Give an example of each interaction.

15. Is light transmitted through the frosted glassshown below? Explain.

16. How many primary colours does an LCD orplasma display need to produce all the coloursof the rainbow?

17. Use the ray model of light to describe thedifference between penumbra and umbra.

Ray diagrams model the behaviour oflight in mirrors and lenses.

18. (a) State the law of reflection.

(b) Does the reflected ray in the illustrationbelow obey the law of reflection? Explainwhy it does or does not.

19. How is a virtual image different from a realimage?

20. Draw a ray diagram to show why your imageis reversed in a plane mirror.

21. How is the focal point of a mirror differentfrom the vertex?

22. (a) Draw a ray diagram of an object 0.75ffrom a concave mirror.

(b) Draw a ray diagram of an object 0.75ffrom a convex mirror.

23. What are two versions of the magnificationformula?

24. State two uses for:

(a) a concave mirror

(b) a convex mirror

25. What is the definition of refraction?

26. Which substance refracts light more, water orglass? Explain why.

27. What is the speed of light?

28. (a) What is the definition of index ofrefraction?

(b) What is the formula for calculating theindex of refraction of a material?

29. What is a common example of dispersion?

30. State the quantities that are related by Snell’slaw.

31. (a) Define critical angle.

(b) How can the value of the critical angle bemeasured?

32. How can you tell the difference betweenregular and diffuse reflection?

33. Which will be larger: the critical angle at anair-glass interface or the critical angle at awater-glass interface? Explain.

34. How does a mirage form? k

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35. (a) Draw a ray diagram for an object 0.75ffrom a converging lens.

(b) Draw a ray diagram for an object 1.25ffrom a converging lens.

36. State the thin lens equation.

37. In the thin lens formula for a convex lens,state when the image distance is:

(a) positive

(b) negative

38. Explain the appearance of the reflection ofthe building in the photograph below.

Question 38

Optical devices help us see fartherand more clearly than we can withunaided eyes.

39. List two parts of the eye that can refract light.

40. What structure controls the amount of lightthat enters the eye?

41. What features of an image are primarilycollected by:

(a) rods

(b) cones

42. State the cause of:

(a) far-sightedness

(b) near-sightedness

43. (a) What type of vision problem does the eye below have?

(b) Copy the diagram into your notebook. Adda correcting lens to your diagram, andshow how the lens bends the light rays tofocus the image on the retina.

44. Laser eye surgery can be used in some casesto correct far-sightedness and near-sightedness. What are three other conditionsof the eye that can be treated with lasersurgery?

45. Compare the features of an image from atelephoto lens and an image from a wide-angle lens.

46. Use a labelled ray diagram to show how animage is produced in a microscope.

47. (a) What type of telescope is the preferredtype for large astronomical observatories?

(b) Why is it preferable?

48. How is laser light different from ordinarylight?

49. How does photonics model properties oflight?

Connect Your Understanding

50. Draw a ray diagram and write a shortexplanation to show why it is sometimesdifficult to reach a coin that is underwater in a pond. c

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Question 43

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51. A flashlight does not lose power as you walkaway from it, but as you get farther andfarther, it appears to be less and less bright.Explain why.

52. Describe three situations where sunlight isseen as the visible spectrum.

53. You are standing outside in the dark, waitingfor a fireworks display, and an extremelybright flash goes off right above you. Describethe behaviour of your pupils before, during,and after the flash.

54. When part of the Moon passes throughEarth’s umbra, the result is a partial lunareclipse, as shown below. What happens whenthe entire Moon passes through Earth’sumbra? Draw a labelled diagram as part ofyour answer.

Question 54

55. If you wish to take a picture of faint stars in the night sky, how should you adjust your camera?

56. Describe how night vision goggles enhancehuman vision.

57. Many grocery stores carry “reading glasses”that you can buy to help you read small print.What kind of lenses do you think theseglasses use? Explain.

58. Explain why you agree or disagree with thefollowing statements. For any you disagreewith, provide the correct statement.

(a) The normal is drawn at a 90° angle to themirror or lens.

(b) When light is reflected from a curvedmirror, the angle of incidence is twice theangle of reflection.

(c) If you want to see farther into space, builda telescope with a bigger convex mirror.

(d) The two main lenses of the microscopeare the eyepiece and the objective lens.

59. Why is it important that a optical fibre nothave any scratches on its surface?

60. When purchasing a diamond, people oftenuse a microscope to look for tinyimperfections within the diamond. In whichcase would the imperfections be more visible,with the diamond immersed in water or inair? Why?

61. A hiker sees a mirage of trees in the sky. Drawa diagram to show how this is possible. Labelthe different air temperature regions. c

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62. Describe what is happening in the followingphotograph.

Question 62

Skill Practice

63. A movie projector magnifies an image on70.0-mm film to fill a screen 2.40 � 104 mmwide. What is the magnification provided bythe projector?

64. A concave lens produces a virtual image of aflower petal 2.00 cm from the lens. Determinethe magnification of the lens if the petal is8.30 cm from the lens.

65. When light passes through sodium gas at–272°C, it slows to 16.7 m/s. What is theindex of refraction of sodium gas at thistemperature?

66. Light travels through a salt crystal that has arefractive index of 1.52. What is the speed oflight in the crystal?

67. Titan is a moon of Saturn that has liquidmethane in the atmosphere. Liquid methanehas an index of refraction of 1.29. If a beamof light from the Sun approaches theatmosphere of Titan at an angle of 36.0°,what is its angle of refraction?

68. A human hair follicle like the one in thephoto below appears to be 5.5 � 10–3 m inwidth when viewed by a lens that magnifies50 times. What is the actual width of the hairfollicle?

Question 68

69. A lens produces a larger, upright, virtualimage that is 12.25 cm from the lens. Theobject is located 5.10 cm away. What is thefocal length of the lens?

70. A convex lens has a focal length of 1.80 cm. If it is held 3.0 cm from an object, how farfrom the lens is the image formed?

71. A far-sighted person wearing a pair of glasseslooks at the soup display in the grocery store.If the convex lenses in the glasses have a focallength of 2.40 m and form a virtual image 2.60 m from the lenses, how far away is thedisplay? k

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72. Follow these steps to find the relationshipbetween the focal length of a sphericalconcave mirror and its radius of curvature:• Draw a concave mirror with a radius of at

least 20 cm.• Mark the centre of the mirror on the

principal axis.• Draw a ray parallel to the principal axis, no

more than 3 cm away from the axis.• Draw a dotted line from the point of

incidence to the centre of the mirror.This is the normal.

• Use the law of reflection to draw thereflected ray.

• Locate where the ray crosses the principalaxis. This is the focal point.

(a) How do you know the dotted line is thenormal?

(b) How can you be sure that you have foundthe focal point?

(c) Compare the radius and the focal length.Hypothesize their relationship.

(d) Describe how you might verify thisrelationship.

Revisit the Big Ideas and FundamentalConcepts73. (a) Describe the differences between

refraction and reflection as a way tochange the direction of a light ray.

(b) Describe how our understanding of theseprinciples benefits society.

74. How have various optical technologieschanged human perceptions of the naturalworld?

75. How have optical technologies such ascellphone cameras and security cameraschanged human behaviour?

Science, Technology, Society,and the Environment

76. Describe some ways that optical devices haveextended human capabilities and reduced theimpact of disease, wear and tear, and traumaon the human eye.

77. What are three different ways that humanhealth has been affected by opticalinstruments?

78. How have optical fibres enhanced our abilityto communicate information?

79. (a) Describe an example of when you thinkdigital manipulation of an image is a goodidea.

(b) Describe an example of when you thinkdigital manipulation should not beallowed.

Reflection80. What can you explain about light and the way

it interacts with matter that you were not ableto before reading this unit?

81. Explain why it is important for you tounderstand properties of light and optics inyour daily life.

82. (a) Choose an optical device that you thinkhas affected your life the most.

(b) Explain how it has contributed to yourlife.

83. What ideas in this unit are you are interestedin learning more about? c

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