EM Spectrum, Reflection & Refraction Test Name: 1. For each of the diagrams below, an object is shown in position before a concave mirror. The shiny side is on the left, facing the object. For each case, draw two of the principal rays and use them to locate the image (if one exists). Draw the image. Use the rulers provided to ensure lines are straight. Also for each case, circle the descriptors listed on the right that apply to the image. 1
2. For the diagram below, an object is shown in position before a convex mirror. The shiny side is on the left, facing the object. Draw two of the principal rays and use them to locate the image (if one exists). Draw the image and label it. Use the rulers provided to ensure lines are straight. Also circle the descriptors listed on the right that apply to the image. 3. (BONUS) In the diagram below, a person stands to the right of a palm tree as shown. The hot air next to the ground makes it act like a flat mirror. Draw the mirage image of the palm tree and draw two rays from the same point on the tree to show why the image is located where you indicated. 4. In the diagram below, a person stands to the left of a large flat mirror. Draw the image formed and draw two rays to show why the image is at the point you indicated. 2
For the following multiple choice questions, circle the letter for the best answer. 5. Part of a pencil that is placed in a glass of water appears bent in relation to the part of the pencil that extends out of the water. What is this phenomenon called? a. interference c. diffraction b. refraction d. reflection 6. Refraction is the term for the bending of a wave disturbance as it passes at an angle from one into another. a. glass c. area b. medium d. boundary 7. Which of the following is an example of refraction? a. A parabolic mirror in a headlight focuses light into a beam. b. A fish appears closer to the surface of the water than it really is when observed from a riverbank. c. In a mirror, when you lift your right arm, the left arm of your image is raised. d. Light is bent slightly around corners. e. None of these 8. What is the wavelength (in vacuum) of microwaves of 3.0 10 9 Hz frequency? a. 0.060 m c. 0.050 m b. 0.10 m d. 0.20 m 9. The image of an object in a flat mirror is always a. larger than the object. c. independent of the size of the object. b. smaller than the object. d. the same size as the object. 10. When two parallel mirrors are placed so that their reflective sides face one another, images form. This is because the image in one mirror becomes the for the other mirror. a. multiple; object c. inverted; center of curvature b. reduced; virtual image d. enlarged; focal point 11. If you stand 3.0 m in front of a flat mirror, how far away from you would your image be in the mirror? a. 1.5 m c. 6.0 m b. 3.0 m d. 12.0 m 12. A prism disperses white light, forming the ROYGBV spectrum. The best explanation for this phenomenon is that different frequencies of visible light a. Move at different apparent speeds in the prism b. Are reflected inside the prism c. Undergo constructive interference in the prism d. Are absorbed inside the prism 3
13. In the diagram above, the image of object B would be a. virtual, enlarged, and inverted. c. virtual, reduced, and upright b. real, enlarged, and upright. d. virtual, enlarged, and upright 14. In the diagram above, the image of object B would be a. real, reduced, and upright. b. virtual, reduced, and inverted. c. virtual, enlarged, and upright. d. virtual, reduced, and upright. 15. As shown in the diagram below, a beam of light can pass through the length of a curved glass fiber. This phenomenon is possible due to the effect of a. polarization b. dispersion c. total internal reflection d. diffraction e. none of these 16. A ray is reflected from a surface as shown in the diagram to the right. Which letter represents the angle of incidence? a. A b. B c. C d. D 4
17. The diagram below represents the path of waves passing from medium A into medium B. As the waves enter medium B, their apparent speed a. decreases b. increases c. remains the same 18. Which diagram below best illustrates wave refraction? The following two questions use the table at the right which gives the index of refraction for several materials. 19. The speed of light is fastest in a. Diamond b. Crown glass c. Water d. Lucite 20. Total internal reflection can occur for light passing from Crown glass into a. Diamond b. Water c. Carbon disulfide material n diamond 2.419 Crown glass 1.523 Carbon disulfide 1.632 water 1.33 Air ~ 1 Carbon tetrachloride 1.461 Lucite 1.4 21. If a ray of light is incident upon an air surface at an angle greater than the critical angle, the ray will a. Partly refract and partly reflect b. Reflect only c. Refract only d. Partly refract and partly diffract 5
22. The diagram below represents a light ray traveling from Crown glass into air. The position of the light source is changed to vary the angle. As approaches the critical angle, the angle of refraction approaches a. 90 b. 0 c. 180 d. 41 e. none of these 23. A ray of light AB in air strikes a piece of glass at an incident angle as shown in the diagram below. Which of the following diagrams best illustrates the ray s reflection and refraction? 6
24. In the diagram to the right, a ray of light enters a transparent medium from air (n = 1). The angle X is 45 and angle Y is 30. a. What is the index of refraction of the medium? b. What is the apparent speed of light in the medium? 25. A mail truck moving down the street at a very high rate of speed (near the speed of light), sees a dog and its owner length contracted as shown in the diagram to the far right. The picture on the left shows the dog and owner as seen by someone who is not moving past them. a. Calculate the gamma factor. 1.2 m 0.6 m b. Calculate the speed of the mail truck in terms of the speed of light. c. What would happen to the observed width of the man and dog if one passes them going faster and faster approaching the speed of light? d. Imagine that you are riding a light wave and moving at speed c. What would be the observed width of the man and dog? Explain very briefly what would happen to the width of the Universe if one were able to travel at the speed of light. 7
26. The wavelength of light at the boundary between red and infrared is nm. 27. The wavelength of light at the boundary between violet and ultraviolet is nm. 28. The diagram to the right shows white sunlight as it enters a raindrop and refracts twice. Which ray (A or B) represents violet light? Explain briefly. 29. A ray of light in air strikes side A of a glass prism as shown. a. Draw the normal line for side A. b. Draw a possible path for the light through the prism. c. Draw the normal line for side B where the light strikes it. d. Draw a possible path for the light after passing through side B. Side A Side B 30. Han Solo and Chewbacca ( Chewie ) the Wookie are positioned as shown on the shiny side of a flat mirror. a. Draw dots to represent the location of the images formed of Han and Chewie. b. Draw lines to indicate the range of images that Chewie can see from his position. c. Can Han see Chewie s image? Han Chewie 8
31. A spear fisherman stands on the shore and looks into the clear water as shown in the diagram below. A fish is located in the water at the position shown. Draw a ray of light from the fish to the fisherman s eye, showing the refraction that occurs at the surface. Also draw the normal line to the surface at the point where the ray strikes the surface. Draw a dotted image of the fish at the position where the fisherman thinks the fish is located. He sees the fish as (circle one) HIGHER LOWER than it actually is. 32. Using the table below, fill in the three missing portions of the EM spectrum. Radio Infrared ROYGBV X-rays waves waves Longest Shortest End of Test 9