Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Ch 14 and 15 Refraction, Interference, and Diffraction of Light NOTES: Unit Objectives What you should know when all is said and done: 1. Describe properties of waves that show how light behaves as a wave such as: A) Refraction. Compare the speed of light through media with different optical densities and explain why dispersion occurs. B) Interference. Describe how interference patterns are formed from double slits, diffraction gratings, and in thin films. C) Huygen’s Principle and Diffraction. Explain some of the uses of diffraction. 2. Use the ray model of light and Huygens’ Principle to find the direction a light ray would travel upon crossing the boundary between media with different optical densities (undergoing refraction). 3. Find focal points for curved lenses, and relate to the center of curvature. 4. Trace ray diagrams for curved lenses to find images. 5. Distinguish between real and virtual images. 6. Explain how the eye works, and how vision is corrected. 7. Explain how optical instruments work (i.e. the camera, microscope). 8. Distinguish between spherical and chromatic aberration with lenses and understand how each are corrected. Worksheet 1: Ch 14 section 1 Refraction (p. 484 – 489) Vocabulary A. Angle of Incidence B. Angle of Refraction C. Concave Lens D. Convex Lens F. Index of Refraction G. Magnification H. Optically Dense I. Refraction 1. ______ The bending of light at the boundary between two media. 2. ______ A transparent refracting device that is thinner in the middle than at the edges. 3. ______ If the angle of refraction is smaller than the angle of incidence, the medium in which the angle is smaller is more _____. 4. ______ The angle that a refracted ray makes with the normal. 5. ______ For light going from a vacuum into another medium, the constant n is the ____. 6. ______ A transparent device that cause light rays to converge. 8. ______ The angle that an incoming beam makes with the normal. 9. ______ The ratio of the size of an image to the size of the object. 11. Which labeled line represents the incident ray? How can you tell? Medium 1 C 12. Which line represents the refracted ray? How can you tell? B F 13. Which line represents the boundary between two media? 14. Which line represents the normal? How can you tell? Medium 2 A E 15. Which labeled angle represents the angle of incidence? H G 16. Which labeled angle represents the angle of refraction? 17. Which angle is greater: the angle of incidence or the angle of refraction? 18. Which medium is more optically dense? Which has the lower index of refraction? 19. When light passes into a medium in which it travels faster, the light will refract ________ the normal. When light passes into a medium in which it travels slower, light will refract ________ the normal. A) towards, away from B) away from, towards 20. When light passes into a medium that is more optically dense, the light will refract ________ D the normal. When light passes into a medium that is less optically dense, the light will refract ________ the normal. A) towards, away from B) away from, towards 22. In eachdiagram, diagram, draw the "missing" ray incident (either incident or in refracted) in order to show 11. In each draw the "missing" ray (either or refracted) order to appropriately that the direction bending is towardsof or bending away fromisthe normal. or away from the normal. appropriately showofthat the direction towards Light, Refraction and Lenses 12. A ray of light is shown passing through three consecutive layered materials. Observe the direction of bending at each boundary and rank the three materials (A, B and C) in order of increasing index of refraction. < smallest < largest 13. Arthur Podd's method of fishing involves spearing the fish while standing on the shore. The apparent location of a fish is shown in the diagram below. Because of the refraction of light, the observed location of the fish is different than its actual location. If Arthur is to successfully spear the fish, must he aim at, below, or above where the fish appears to be? __________ Explain. © The Physics Classroom, 2009 Page 4 WS 2: Ch 14 section 1 Index of Refraction (p. 484 – 489) 1. Every transparent material is characterized by a unique index of refraction value (n). The index of refraction value is a numerical value that provides a relative measure of the speed of light in that particular material. Light travels __________________ (fastest, slowest) in media with a higher index of refraction value. 2. The speed of light (v) in a material is determined using the speed of light in a vacuum (c) and the index of refraction (n) of the material. Calculate the speed of light in the following materials. n = c / v = (3.00 x 108 m/s) / v A) water (n = 1.33): B) glass (n = 1.50): C) ice (n = 1.31): D) diamond (n = 2.42): 3. Which of the following affects the index of refraction? A) The angle of incidence B) the nature of the transparent medium C) The wavelength of light D) All of the above 4. _______ is the bending of light (or change in direction) as it travels from one medium to another. A) Reflection B) Index of refraction C) Dispersion D) Refraction 5. For light going from a vacuum into another medium, the constant n is the ____. A) Reflection B) Index of refraction C) Dispersion D) Refraction 6. If light slows down when going through a medium, it can be said that the medium has a high A) Reflection B) Index of refraction C) Dispersion D) Refraction 7. The relationship between the angles of incidence and refraction with the index of refraction of 2 materials is called ______________________ law. WS 3: Ch 14 section 2 Thin Lenses (p.490 – 497) 1. Use refraction principles to sketch an approximate path of light as it enters and exits the lens. Think FST (fast to slow = toward) and SFA (slow to fast = away). Trace the path of the rays into, through and out of the lens. Repeat the procedure for the light rays exiting the lens and trace the emerging light rays. Place arrowheads on all light rays. Light, Refraction and Lenses Name: Lenses Read from Lesson 5 of the Refraction and Lenses chapter at The Physics Classroom: 2. Explain why lenses (like the one on the http://www.physicsclassroom.com/Class/refrn/u14l5a.html left above) are called "converging" lenses. http://www.physicsclassroom.com/Class/refrn/u14l5b.html http://www.physicsclassroom.com/Class/refrn/u14l5c.html Connection: Refraction and Lenses: sublevel 7 3. Converging lensesMOP are _____ at the center and _____ at the edges. A) thickest, thinnest B) thinnest, thickest 1. Converging lenses are _____ at the center and _____ at the edges. a. thickest, thinnest b. thinnest, thickest 4. Diverging lenses are _____ at the center and _____ at the edges. lenses are _____ at the center and _____ at the edges. A) thickest, thinnest 2. B) Diverging thinnest, thickest a. thickest, thinnest b. thinnest, thickest Consider the diagramConsider at the right in answering the next two questions. the diagram at the right in answering the next two questions. 5. List the letters of all3. theList converging lenses. the letters of all the converging lenses. 6. List the letters of all4. theList diverging lenses. the letters of all the diverging lenses. ' For each statement below, write true orprinciples rewrite the italicized part to make theofstatement true. and exits the lens. T 5. Use refraction to sketch an approximate path light as it enters 7. __________________ FST A convex lens can be used as a magnifying glass. and SFA. Trace the path of the rays into, through and out of the lens. Repeat the procedu the light rays exiting the lens and trace the emerging light rays. Place arrowheads on all light r 8. __________________ When a lens is used as a magnifying glass, the object is placed outside the focal point. 9. __________________ Images produced by convex lenses are always real. 10. __________________ The images produced by concave lenses are always inverted. 11. __________________ A concave lens is thinner in the center than at the edges. 12. __________________ Concave lenses refract rays so that the rays converge. #1: #2: #3: 10. State the three rules of refraction for diverging lenses: 13. Identify the following statements as being either true (T) or false (F). #1: A) If reflected or refracted rays diverge, there is no image. _______ _______ B) If an object is located in front of a focal point, there is no image. #2: C) Virtual images cannot be seen. _______ _______ D) All images are formed by the actual convergence of reflected or refracted light. #3: E) Just three rays of light from an object can intersect at the image location. _______ 14. The belowdepict depictthe the refraction of light through various lenses. Circle the diagrams 11. The diagrams diagrams below refraction of light through various lenses. List the diagrams that show the of of light. _________ thoseshow whichthe show the improper refraction of that show theproper properrefraction refraction light. For thoseFor which improper refraction of light, light, either correct the diagrams by showing the proper refracted or explain what is wrong either correct the diagrams by showing the proper refracted rays rays or explain what is wrong with with the refracted the refracted rays. rays. © The Physics Classroom, 2009 Page 10 WS 4: Ch 14 section 2 Ray Diagrams with lenses (p. 490 – 497) Light, Refraction and Lenses 1. The diagram below shows an arrow object positioned in front of a converging and a diverging lens. Three incident rays are shown. Construct the corresponding refracted rays. Show 8. The diagram below shows an arrow object positioned in front of a converging and a diverging lens. arrowheads. Three incident rays are shown. Construct the corresponding refracted rays. Show arrowheads. 9. State the three rules of refraction for converging lenses: #2: #2: 2. State the three rules of refraction for converging lenses: #1: #1: #3: #3: Light, Refraction and Lenses 10. State the three rules of refraction for diverging lenses: Name: #1: the three rules of refraction for diverging lenses: 3. State Ray Diagrams for Converging Lenses #1: Read from Lesson 5 of the Refraction and Lenses chapter at The Physics Classroom: #2: #2: http://www.physicsclassroom.com/Class/refrn/u14l5da.html http://www.physicsclassroom.com/Class/refrn/u14l5db.html MOP Connection: Refraction and Lenses: sublevels 8 and 9 #3: #3: 11. For the following lenses and corresponding object positions, construct ray diagrams. Then describe the Location of the image, Orientation (upright or inverted) of the image, the relative Size of the image (larger or smaller than object), and the Type of image The diagrams below depict the refraction of light various lenses. the diagrams that (real or virtual). For through Case 4, merely construct the List ray diagram. show the proper refraction of light. _________ For those which show the improper refraction of 3. DRAWING RAY DIAGRAMS FOR CONVEX LENSES. Use therays rules above to dray ray of travel of the ray. light, either correct the diagrams byNOTE: showing the proper or explain what wrong 1) All light rays refracted have arrowheads which indicate theisdirection with the rays. 2) Always in the image once located (an arrow is a good representation). diagrams andrefracted complete the “LOST” description of thedraw image. 3) Exactness counts. Use a straight-edge and be accurate. Case 1: If the object is located beyond 2F: Case 1: If the object is located beyond 2F: Description of Image: Location: ______________________________ O: Upright or Inverted S: Magnified or Reduced T: Real or Virtual Description of Image: Location: O: Upright or Inverted S: Magnified or Reduced T: Real or Virtual Light, Refraction and Lenses Description of Image: Case 3: If the object is located between 2F and F: Location: O: Upright or Inverted Case 2: If the object is located between 2F Case 4: If the object is located at F: and F: S: Magnified or Reduced T: Real or Virtu Description of Image: Location: _________________________________ O: Upright or Inverted S: Magnified or Reduced T: Real or Virtual Description of Image: Location: O: UprightRequired or Inverted S: Magnified or Reduced No Description Case If the object is located at F: F and the lens: Case 5: 4: If the object is located between Case 3: If the object is located between F and the lens: T: Real or Vi Name: Description of Image: Light, Refraction and Lenses Location: _________________________________ O: Upright or Inverted Ray Diagrams for Diverging Lenses S: Magnified or Reduced T: Real or Virtual Read from Lesson 5 of the Refraction and Lenses chapter at The Physics Classroom: http://www.physicsclassroom.com/Class/refrn/u14l5ea.html http://www.physicsclassroom.com/Class/refrn/u14l5eb.html MOP Connection: Refraction and Lenses: sublevels 10 and 11 For the following lenses and corresponding object positions, construct ray diagrams. Then describe the Location of the image, Orientation (upright or No inverted) of the image, the relative Size of the image (larger Description Required Description ofand Image: or smaller than object), the Type of image (real or virtual). Case 5: If the object is located between F and the lens: Location: O: Upright or Inverted or Reduced T: Real or Virtu 4. DRAWING RAY DIAGRAMS FOR CONCAVE LENSES. UseS:theMagnified rules above to dray ray All light rays haveimage. arrowheads which indicate the direction of travel of the ray. diagrams and complete the NOTE: “LOST” 1) description of the 2) Always draw in the image once located (an arrow is a good representation). 3) Exactness counts. Use a straight-edge and be accurate. ©1:The Physics Classroom, 2009 Case 1: If the object is Case located away the lens: Iffar the objectfrom is located far away from the lens: Description of Image: Location: ______________ O: Upright or Inverted S: Magnified or Reduced T: Real or Virtual Description of Image: Location: O: Upright or Inverted S: Magnified or Reduced T: Real or Vi Description of Image: Location: © The Physics Classroom, 2009 O: Upright or Inverted S: Magnified or Reduced T: Real or Virtual Description of Image: Location: O: Upright or Inverted S: Magnified or Reduced T: Real or Virtual Case 2: If the object is located nearby the lens: Case 2: If the object is located nearby the lens: Description of Image: Location: ________________ O: Upright or Inverted S: Magnified or Reduced T: Real or Virtual Description of Image: Location: 5. Several statements about images are given below. Identify which optical device applies to the given statement. Place the appropriate marks in the blanks.S:Mark all thatorapply. O: Upright or Inverted Magnified Reduced T: Real or Virtual A = plane mirrors B = concave mirrors C = convex mirrors D = converging lenses E = diverging lenses ______________ a. Are of producing images. © capable The Physics Classroom,real 2009 ______________ b. Only produce virtual images. ______________ c. Are capable of producing enlarged images. ______________ d. Can only produce images which are smaller than the object. ______________ e. Capable of producing images the same size as the object. WS 5: Ch 14 section 2 Eyeglasses and contact lenses (p.498 -501) 1. What type of vision impairment is represented in the diagram below? How is this corrected? 2. What type of vision impairment is represented in the diagram below? How is this corrected? 3. What is astigmatism and how is it corrected? 4. What happens to your vision as you age? How is this corrected? 5. Both compound microscopes and refracting telescopes use ____________________________ 6. High quality cameras use both _______________________ and ______________________ lenses to minimize _______________________________. (p.500) WS 6: Ch 14 section 3 Optical Phenomena (p. 502 – 507) 1. __________________________________________describes the incident angle that causes a refracted ray to lie along the boundary of a substance. 2. __________________________________________is when light passes form one medium to a less optically dense medium at an angle so great that there is no refracted ray. 3. The complete reflection that takes place within a substance when the angle of incidence of light striking the surface boundary is greater than the critical angle is called A) critical angle B) index of refraction C) complete internal reflection D) dispersion 4. The angle of incidence at which the refracted light makes an angle of 90 degrees with the normal is called A) critical angle B) index of refraction C) complete internal reflection D) dispersion 5. Light will undergo total internal reflection only when it is _______. Choose two. A) in the less dense medium traveling towards the more dense medium B) in the more dense medium traveling towards the less dense medium C) in the medium where it travels slowest, moving towards the medium where it travels fastest D) in the medium where it travels fastest, moving towards the medium where it travels slowest Complete the following blanks by answering questions #6 and #7: The critical angle is the angle of (#6) that causes light to (#7) . 6. Referring to the statement above: A) incidence B) refraction C) reflection 7. Referring to the statement above: A) cross the boundary without refracting B) undergo refraction at the same angle as the angle of incidence C) refract at an angle of refraction of 90 degrees D) reflect at the same angle as the angle of incidence 8. Examples of the use of total internal reflection are____________________________________ and _________________________________ 9. A mirage is produced by ______________________light rays in the atmosphere when there are large _________________________________________between the ground and the air. 10. _______ is the separation of light into its spectrum of colors because light waves of different wavelenghts change speed by different amounts when going through transparent materials. A) Reflection B) Index of refraction C) Dispersion D) Refraction 11. When entering a new transparent medium, blue wavelengths are bent _________(more/less) than red wavelengths, causing dispersion. 12. Describe the three physics principles that cause rainbows to appear.(p.506) 1) 2) 3) 10. Describe two lens imperfections: chromatic aberration and spherical aberration. (p.507) Wave Interference (Qualitative) 1. The intersection of two crests is shown. Sketch the position of these two crests a short time later and indicate the direction of the movement of the intersection. WS 7: Ch 15 section 1 Interference (p. 520 – 525) (See also physicsclassroom.com “2 point source interference” lesson 1b) 2. The 1. following wave frontbetween model represents crestsofastwo darkorlines. marksisshowing the outward The correlation the phases moreThe waves called ______________. This is propagation arephase left outdifference for clarity. between two waves is ___________________. This can only when the happen if both waves have the same ____________________. C When 2 waves overlap and areAprojected onto a screen, an __________________ pattern appears. A point on the screen where two ____________ meet results in a bright fringe and a point on the screen where two _________________ meet results in a dark fringe.. B 2. The pattern below shows two wave sources overlapping. Describe the interference occurring at points A, B, and C. A) If the double crests define a maximum line and the combination of a crest and a trough define a minimum or node line, what does a double trough define? 3. If the double crests define a maximum line and the combination of a crest and a trough define a minimum or node line, what does a double trough define? Show with diagrams. B) On the pattern below draw the minimum lines (antinodal lines). Where the lines come out the 4. On the drawfirst, the maximum linesthird (antinodal Where lines(7 come outtotal) the top toppattern label below the zero, second and orderlines). lines on eachtheside. lines label the zero, first, second and third order lines on each side. (7 lines total) S1 C)Instruction If this pattern ©Modeling Programwere 2008 S2 two coherent light a screen, describe 1 sources projected onto L2-Wave Model ws 4a v4.0 what you would see at the positions you marked. 8. a. For each of the lettered points on the interference pattern below answer these questions: How 3. The diagram showfrom two each waves interfering withmany eachwavelengths other. many below wavelengths source is it, by how do the two paths differ and whether there constructive or or destructive at the point. A) Label each point as is constructive destructiveinterference interference. A C B F E D S2 S1 Letter Wavelengths from Wavelengths from S2 S1Constructive or Destructive Location Interference? A B A C B D E C F Difference Location Constr or Destr Constructive or Destructive Interference? D E F b. Explain in a sentence how the path difference between a point and the waves sources 4. Rainbow patterns on “thin films” of transparent material such as an oil spill or a determinescan the be typeseen of interference. sop bubble. This occurs because of (see physicsclassroom.com “thin film interference” lesson 1C) A) refraction and dispersion of the white light into all colors of the rainbow B) diffraction C) reflection of colors from different surfaces D) interference of light waves reflecting off the top and bottom surfaces of the film 9. This question is on the next page, there was not room for it here. 5. When you see streaks of color on the surface of a bubble or thin film of oil, this is called ________________________________________. ©Modeling Instruction Program 2008 3 L2-Wave Model ws 4a v4.0 WS 8: Ch 15 section 2 Diffraction (p. 526 – 533) 1. The bending of a wave when encountering an obstacle, opening, or edge is called ________________________. 2. An interference pattern, like the one produced with double slit interference, is produced when light passes through a single narrow slit. This is called a _________________________ pattern, and is evidence of light interfering with itself. In order to understand this phenomena, we invoke __________________________ principle, which states that a single slit can be viewed as a source of multiple point sources (wavelets) of light. In other words, light from ________ portion of the slit can interfere with light from _________________ portion of the slit. 3. Diffraction becomes more evident as the width of the slit is ________________________. 4. In diffraction, longer waves tend to bend ________________(more/less) than shorter waves. For this reason, ___________________ waves are best suited for communication around buildings and mountains. 5. Diffraction is the reason why the edges of shadows ___________(are/aren’t) sharp. 6. Diffraction gratings are used inside ______________________ to disperse white light in order to see characteristic wavelengths that are unique to each ____________________. Sketch the interference of light with itself through a single slit using Huygen’s principle of wavelets.