Light and Refraction Study Guide Answer Keys

TEACHER RESOURCE PAGE13 Light and Reflection FLAT MIRRORS 1. 2. 3. 4. 9. b 5. c d 6. d a 7. b b 8. b Answers may vary. Sample answer: Virtual; the rays that form the image appear to come from a point behind the mirror. Eye p q Solution Rearrange the equation to isolate the image distance, and calculate. 1/q ϭ 1/f Ϫ1/p 1/q ϭ 1/20.0 cm Ϫ 1/50.0 cm ϭ 0.0500/1 cm Ϫ 0.0200/1 cm ϭ 0.0300/1 cm q ϭ 33.3 cm 13 Light and Reflection COLOR AND POLARIZATION c 5. b a 6. a d 7. c b 8. d Answers may vary. Sample answer: In the correct proportions, a mixture of the three primary pigments produces a black mixture because all colors are subtracted or absorbed from white light. 10. Answers may vary. Sample answer: By rotating a polarizing substance in the beam of light. If the light intensity changes as the polarizing substance is rotated and eventually no light can pass through, the beam of light is polarized. 1. 2. 3. 4. 9. 10. 1 h q qЈ 2 hЈ Object Image Mirror 13 Light and Reflection CURVED MIRRORS a 5. b b 6. c c 7. d b 8. a Answers may vary. Sample answer: A spherical mirror is a portion of a spherical shell. In contrast, a parabolic mirror is made from segments of a reflecting paraboloid. With a parabolic mirror, all rays parallel to the principal axis converge at the focal point regardless of where on the mirror’s surface the rays reflect. Thus, a real image forms without spherical aberration. 10. 33.3 cm Given f ϭ ϩ20.0 cm p ϭ ϩ50.0 cm The mirror is concave, so f is positive. The object is in front of the mirror, so p is positive. 1. 2. 3. 4. 9. 14 Refraction REFRACTION d 5. a c 6. b a 7. c b 8. d Answers may vary. Sample answer: As wave fronts enter a transparent medium, they slow down, but the wave fronts that have not yet reached the surface of the medium continue to move at the same speed. During this time the slower wave fronts travel a smaller distance than do the original wave fronts, so the entire plane wave changes directions. 10. 31.6° Given ni ϭ 1.333 nr ϭ 1.458 qi ϭ 35.0º 1. 2. 3. 4. 9. Copyright © by Holt, Rinehart and Winston. All rights reserved. Holt Physics 165 Answer Key 1 ϫ 102 nm 1. c b 6.0400 0.29º 15 Interference and Diffraction INTERFERENCE a 5. Coherent waves have wavelengths that are equal and travel in phase. a b 8. ΂ ΃ ΂ ΃ 47. 8.1 ϫ 10Ϫ3 mm q ϭ 17. 3. but the violet light. 4. All rights reserved.0°) ᎏᎏᎏ ϭ 1 6. 4. 1. 9.0 cm 0. Sample answer: When an observer views a raindrop high in the sky.TEACHER RESOURCE PAGE Solution Rearrange the Snell’s law. 2. d d 6.6° 1. sin qc ϭ nr/ni.361 nr ϭ 1. b a 7. a c b d Copyright © by Holt. 3. and solve for c. c d 8. c Answers may vary. passes over the observer because it deviates from the path of the white light more than the red light does. d b 6.00 ϫ 10Ϫ2 cm Given p ϭ 25. Incoherent waves usually do not have equal wavelengths and do not travel in phase. like the other spectral colors.0 cm 25.1 ϫ 10Ϫ3 mm)(sin17. 10. and solve for qr. 10. 6. a b 7.0 cm f ϭ 20. 7. c b d a 5.29° ΄ ΅ Given ni ϭ 1. 9.361 ni 1. 3. Rinehart and Winston. ni qr ϭ sinϪ1 ᎏᎏ(sin qi) ϭ nr 10. 1. d Answers may vary.0 cm Solution Rearrange the thin lens equation.333 sinϪ1 ᎏᎏ(sin 35.458 ΄ ΅ 14 Refraction THIN LENSES b 5.00 ϫ 10Ϫ2 cm 1. Holt Physics 166 Answer Key . c a 7. 4. 4.1 ϫ 10Ϫ4 mm ϭ 6.0500 0.0° mϭ1 Solution dsinq ϭ ml dsinq l ϭ ᎏᎏ ϭ m (2. 2. 2. 9. 1 1 1 ᎏᎏ ϩ ᎏᎏ ϭ ᎏᎏ. Sample answer: The image formed by the first lens is treated as the object for the second lens. c 5. c d 8. ni sin qi ϭ nr sin qr. q f p 1 1 1 1 1 ᎏᎏ ϭ ᎏᎏ Ϫ ᎏᎏ ϭ ᎏᎏ Ϫ ᎏᎏ ϭ q f p 20.0100 ᎏᎏ Ϫ ᎏᎏ ϭ ᎏᎏ 1 cm 1 cm 1 cm q ϭ 1. and solve for q. 15 Interference and Diffraction DIFFRACTION 1. 2.0º) ϭ 31.000 Solution Use the critical angle equation. 3.000 nr qc ϭ sinϪ1 ᎏᎏ ϭ sinϪ1 ᎏᎏ ϭ 1. 47. a Both coherent and incoherent waves are periodic disturbances that transfer energy. 14 Refraction OPTICAL PHENOMENA 1. 610 nm Given d ϭ 2. the red light reaches the observer. q ϭ Ϫ20.00 cm R ϭ 40. The index of refraction of the first medium must be greater than the index of refraction of the second medium.0 cm q ϭ 30.0 cm. 6. b 11. (Ϫ20. 2. c b 12.e. Illuminance is the ratio of lumens/m2. a d 19. The image is upright and virtual.0 cm q ϭ Ϫ20.0 cm 30. 22. the image is infinitely far to the left and therefore is not seen. a c 13. Illuminance is a derived unit that indicates the relationship between luminous flux and the distance from the light source squared. 15. the angle of incidence is equal to the angle of reflection. 4.0 cm Solution Since R ϭ 40. Rearrange the mirror equation. a c 14. 19. Rinehart and Winston. 5. Mirror 3 1 Principal 3 axis C Object F 1 Front of mirror Back of mirror Refraction CHAPTER TEST A (GENERAL) 1.0 cm Given f ϭ 10.0 cm p ϭ 10. b 20. 9. 7.0 cm 1 2 1 ϭ ᎏᎏ Ϫ ᎏᎏ ϭ Ϫᎏᎏ 20.0 cm 20. d d c d The ultraviolet portion of the electromagnetic spectrum is made of sufficiently high frequency (i. 12. as shown in the answer diagram. When the candle is at the focal point. M ϭ ϩ2. According to the law of reflection.0 cm 30. All rights reserved.0 ϫ 101 cm behind the mirror. It is measured in lumens.0 cm p 16. 17.TEACHER RESOURCE PAGE 10. b c 20. b a 17. the image is located 2.0 cm 30.0 cm) q M ϭ Ϫᎏᎏ ϭ Ϫ ᎏᎏ ϭ ϩ2. d The speed of light decreases.0 cm p ϭ 15 cm 11.0 cm Since q is negative. 13. 21. c a 16.0 cm Solution Rearrange the mirror equation. 10. a c 18.00 10. 3.00 2 Mirror 2 3 1 C 3 Principal axis 1 F Object Front of mirror Image Back of mirror Given h ϭ 2. 1 1 1 ᎏᎏ ϩ ᎏᎏ ϭ ᎏᎏ.0 cm 20. 52°. 23. f ϭ 20. 14. and solve for p.0 cm 10. and solve for q. 1 1 1 ᎏᎏ ϩ ᎏᎏ ϭ ᎏᎏ. Copyright © by Holt. 18. Electromagnetic waves are distinguished by their different frequencies and wavelengths.. q f p 1 1 1 1 1 ᎏᎏ ϭ ᎏᎏ Ϫ ᎏᎏ ϭ ᎏᎏ Ϫ ᎏᎏ q f p 20. 8. Holt Physics 201 Chapter Test . Luminous flux is a measure of the amount of light emitted from a light source.0 cm 3 1 2 ᎏᎏ Ϫ ᎏᎏ ϭ ᎏᎏ 30. high energy) electromagnetic radiation that can destroy bacteria or other pathogens.0 cm. a d 15. q f p 1 1 1 1 1 ᎏᎏ ϭ ᎏᎏ Ϫ ᎏᎏ ϭ ᎏᎏ Ϫ ᎏᎏ ϭ f q p 10. In order to be seen. 25. 13. and solve for qr.65 7. A light ray represents the direction of propagation of a planar wave front. The rays fan out from the second face of the prism to produce a visible spectrum.0 ϫ 101°) ϭ 18° 1.0500 0.00 sinϪ1 ᎏᎏ (sin 3. to find M. 17. a 16. h hЈ (151 cm) M ϭ ᎏᎏ ϭ ᎏᎏ ϭ 141 h (1.TEACHER RESOURCE PAGE 24. M ϭ ᎏᎏ. This eyepiece. As these wave fronts enter a transparent medium. ni qr ϭ sinϪ1 ᎏᎏ (sin qi) ϭ nr 15.00 ᎏᎏ (sin 28. Holt Physics 202 Chapter Test . no refraction occurs.00 cm 0. d 8.7° Given qi ϭ 28. The light will undergo total internal reflection. 1 1 1 1 1 ᎏᎏ ϭ ᎏᎏ ϩ ᎏᎏ ϭ ᎏᎏ ϩ ᎏᎏ ϭ f q p 20.125 0.07 cm) Copyright © by Holt. inverted image just inside the focal point of the eyepiece. ni sin qi ϭ nr sin qr.63 Solution Rearrange Snell’s law. 2. Earth’s atmosphere and are bent because the atmosphere has an index of refraction greater than that of the near-vacuum of space. 5. ΂ ΃ sin Ϫ1 ΂ 1. a Object Front 2F F F Image 2F Back ΂ ΃ Solution Use the thin-lens equation to find f. b c a a b d Solution Rearrange Snell’s law. Although this results in a change in the overall wavelength of the spherical wave fronts. and solve for qr.63 ΃ 14. Rinehart and Winston. Each colored component of the incoming ray is refracted depending on its wavelength.0 cm 8. the second lens. when the difference between the sub- 12. ΂ ΃ stances’ indices of refraction is the greatest An object placed just outside the focal length of the objective lens forms a real. An atom is many times smaller than a wavelength of visible light.0° ni ϭ 1. c 11. ni sin qi ϭ nr sin qr. 4.0°) ϭ 1. serves to magnify the image. A real. ni qr ϭ sinϪ1 ᎏᎏ(sin qi) ϭ nr 10. which is the superposition of all the spherical wave fronts.175 ᎏᎏ ϩ ᎏᎏ ϭ ᎏᎏ 1 cm 1 cm 1 cm f ϭ 5. Therefore. 16. inverted image that is smaller than the object will form between F and 2F. 1. 3. all of them strike the surface simultaneously and experience a similar change in velocity at the same instant. the object under a microscope must be at least as large as a wavelength of light. All rights reserved.7° Refraction CHAPTER TEST B (ADVANCED) 1. Rays of light from the sun strike Solution Use the magnification of a lens hЈ equation.71 cm 9. there is no change in the direction of the wave fronts relative to each other. 16.00 nr ϭ 1. 6. 50 cm 1. 18.TEACHER RESOURCE PAGE 18. d c 15. since this is a converging lens) Solution Rearrange the thin-lens equation. Rinehart and Winston. 5.7 ϫ 102 nm Copyright © by Holt. Snell’s law states that the angles of refraction will be different for different wavelengths even if the angles of incidence are the same.50 cm pe ϭ 1. 48 cm Given p ϭ 24 cm f ϭ 16 cm (f is positive. b 9.180 cm ϭ 1. and solve for q.0 ϫ 10Ϫ5 m)(sin 2. 3.021 ᎏᎏ Ϫ ᎏᎏ ϭ ᎏᎏ 1 cm 1 cm 1 cm q ϭ 48 cm (since q is positive. 7. and solve for q. q f p 1 1 1 1 1 ᎏᎏ ϭ ᎏᎏ Ϫ ᎏᎏ ϭ ᎏᎏ Ϫ ᎏᎏ ϭ qe fe pe 1.758 0. 6. c d 14. 1 1 1 ᎏᎏ ϩ ᎏᎏ ϭ ᎏᎏ. Resolving power is the ability of an optical instrument to separate two images that are close together.00 cm p0 ϭ 1. a b c d Solution d sin q ϭ ml d sin q l ϭ ᎏᎏ ϭ m 4.8 ϫ 102 nm Interference and Diffraction CHAPTER TEST B (ADVANCED) 1.667 0. 20.8 ϫ 10Ϫ7 m ϭ 4. c 6. spectrometer A spectrometer separates light from a source into its monochromatic components. Rearrange the thin-lens equation. the image is virtual and in front of the lens) Interference and Diffraction CHAPTER TEST A (GENERAL) 1. q f p 1 1 1 1 1 ᎏᎏ ϭ ᎏᎏ Ϫ ᎏᎏ ϭ ᎏᎏ Ϫ ᎏᎏ ϭ q f p 16 cm 24 cm 0. a c 13.7 ϫ 10Ϫ7 m ϭ 7.32 cm Solution The focal length and object distance of the objective lens do not enter into the calculation. b c 12. 8. 2. Dispersion is the process of separating polychromatic light into its component wavelengths because n is a function of wavelength for all material mediums. Holt Physics 203 Chapter Test . 480 nm Solution d sin q ϭ ml d sin q l ϭ ᎏᎏ ϭ m (2.50 cm Ϫ 0. c 5. 17. Ϫ11 cm Given F0 ϭ 1. 16. d (4. 7.32 cm 0. 19. 2.091 ᎏᎏ Ϫ ᎏᎏ ϭ Ϫᎏᎏ 1 cm 1 cm 1 cm qe ϭ Ϫ11 cm (since q is negative.5 ϫ 10Ϫ6 m)(sin 35°) ᎏᎏᎏ ϭ 3 4. or an edge. The image of the objective lens is the object of the eyepiece lens.2°) ᎏᎏᎏ ϭ 2 7. an opening. 19. c a 11.25 cm Fe ϭ 1. 4. All rights reserved.042 0. d b Diffraction is a change in the direction of a wave when the wave encounters an obstacle. 1 1 1 ᎏᎏ ϩ ᎏᎏ ϭ ᎏᎏ. a b 10. the image is real and in back of the lens) 20.063 0. 3.