Quest Chapter 30. Same hint as in #1. Consider the shapes of lenses that make them converge or diverge.

Transcription

1 1 Consider the light rays depicted in the figure. 1. diverging mirror 2. plane mirror 3. converging mirror 4. converging lens 5. diverging lens 6. Unable to determine. 2 Consider the light rays depicted in the figure. 1. converging lens 2. diverging mirror 3. diverging lens 4. converging mirror 5. plane mirror 6. Unable to determine. 3 Consider the light rays depicted in the figure. 1. converging lens 2. plane mirror 3. diverging lens 4. converging mirror 5. Unable to determine. 6. diverging mirror 4 Which of the glass lenses above, when placed in air, will cause rays of light (parallel to the central axis) to converge? 1. Z, R, and Y 2. H and G 3. Z, H, Y, and B 4. Z, Y, and B 5. Z, G, and B 6. H and Y 7. Z, H, and G 8. Z, R, and G 9. Z, H, R, and B 10. R and Y Quest Chapter 30 Look at the behavior of the rays not only their direction. What would a mirror do? Bounce What would a lens do? Bend Are they coming together? Converge Are the splitting apart? Diverge Same hint as in #1. Same hint as in #1. Consider the shapes of lenses that make them converge or diverge.

2 5 Which of the glass lenses above, when placed in air, will cause rays of light (parallel to the central axis) to diverge? 1. H and F 2. N, Z, and B 3. N, W, H, and B 4. N, W, F, and B 5. W and Z 6. N, H, and F 7. N, F, and B 8. W and F 9. N, W, and Z 10. N, H, and Z 6 Poke a hole in a piece of cardboard and hold the cardboard in the sunlight. Note the image of the sun that is cast below. Try a square hole; what is the image of the sun? 1. round 2. triangular 3. hexagon 4. pentagon 5. square 7 An ordinary magnifying glass produces an image which is 1. virtual and erect 2. real and erect 3. virtual and inverted 4. real and inverted 5. none of these Same hint as #4. What shape would you expect? Do you have to move the lens backward? (Yes: Inverted; No: Erect) Does light come from the image location directly to your eye? (Yes: Real; No: Virtual)

3 8 An object is placed at a distance of 1.5 f from a converging lens of focal length f, as shown. What type of image is formed and what is the size relative to the object? 1. Virtual Same size Inverted 2. Real Larger Upright 3. Real Smaller Upright 4. Virtual Larger Inverted 5. Real Smaller Inverted 6. Real Larger Inverted 7. Virtual Smaller Upright 8. Virtual Same size Upright 9. Virtual Larger Upright 10. Virtual Smaller Inverted 9 A converging lens has a focal length of 36.7 cm. If the object is 62.7 cm from the lens, what is the image distance? Answer in units of cm. 10 If the object distance for a converging thin lens is more than twice the focal length of the lens, the image is 1. virtual and erect. 2. located inside the focal point. 3. located at a distance more than 2 f from the lens. 4. located at a distance between f and 2 f from the lens. 5. larger than the object. 11 A convex lens has a focal length of cm. The object distance is cm. Find the image distance. Answer in units of cm. f is the focal distance. Draw the ray diagram. Use an arrow sitting on the principal axis. Two sets of rays. First: From the tip parallel to PA to the center of the lens then through the next focal point and beyond. Second: From the tip through the first focal point to the center of the lens then parallel until it meets the first set of rays. Substitute and solve. Beware of the fractions. Use the equation in #9. Use d o = 2.1f. Find d i. What will happen to d i as d o increases? Use the equation in #9. 12 Find the magnification. M = -d i / d o 13 Suppose you look out the window and see your friend, who is standing 28.3 m away. To what focal length must your eye muscles adjust the lens of your eye so that you may see your friend clearly? Remember that the distance from the front to the back of your eye is about 1.90 cm. Answer in units of cm.

4 14 The distance of the lens in the human eye from the retina, on which the image is focused, is about 1.7 cm. To focus on a book 52.4 cm from the eye, what must the focal length of the eye be? Answer in units of cm. 15 Compare a lens used to capture an image to the lens used to project that image back onto a screen for viewing. 1. Different types 2. Same types 16 Why is the image projected onto the back of the retina in your eyes upside down? 1. None of these 2. The focal length of the eye is very long. 3. The eye is a diverging lens. 4. The eye is a converging lens. 17 When your eyes are submerged in water, do light rays coming from water to your eyes bend more, less, or the same as in air? 1. The same 2. It depends on the speed of the water. 3. Less 4. More What do they have to do? What type of lenses do that? What type of lens inverts that way? The question is whether water-eye has more bending than air-eye. To figure this out, you have to compare the indices of refraction. Check out this site: How does the index of refraction for water (1.33) compare to the structures of the eye? How does that compare to air?

5 If the indices are close do they refract more or less? Check out Snells Law p451.