discussion 12

Physics 2140 Discussion 12 worksheet NAME ________________________________________________________ Learning outcomes: • Predict qualitatively and quantitatively the formation of images by mirrors and lenses • Predict the formation of images in the eye and the method for correcting defects in human vision 1. A diverging lens has a focal length of −4 #$ , and an object is placed 12 #$ in front of the lens, as shown in the figure. a. Use the “easy -to- draw” rays to find the image location on the figure above. What sort of image is it? b. Use the lens equation to mathematically determine the location of the image. c. What do you notice about the image distance you calculated in part b? What does this tell you about where the image is located? Is your answer to part b consistent with the ray diagram you drew in part a? This study source was downloaded by 100000817901397 from CourseHero.com on 11-30-2023 08:49:33 GMT -06:00 https://www.coursehero.com/file/43266418/Discussion-12-worksheet-2-SOLUTIONSpdf/ maryam jundid => z => > = => # -- - - - - * me # - virtual -Upright - shrunken ent t i = - 3cm The image distance is negative , and the image is Virtual and 3cm infront of the lens . : This matches the ray diagram above . =>

2. Assume that you have normal vision: the near point of your eye is 25 #$ and the far point is ∞ . The distance between your eye lens and retina is 1.7 #$ . You look at the letters on this page with your eye, holding the page at your near point as in the figure below. Your eye lens adjusts to form a clear image of the letters on your retina. a. Is the image that forms on your retina real or virtual? Is the lens in your eye converging or diverging? Explain how you can tell. b. A single letter on this page has a height of 0.3 #$ . How tall is the image of this letter on your retina? c. Is the image on your retina upright or inverted with respect to the letters on the page? Explain how you can tell. d. What must be the focal length of your eye lens in order to see an object at your near point, as in the situation described above? We will call this focal length - . . This study source was downloaded by 100000817901397 from CourseHero.com on 11-30-2023 08:49:33 GMT -06:00 https://www.coursehero.com/file/43266418/Discussion-12-worksheet-2-SOLUTIONSpdf/

d. Suppose you place the necessary corrective lens directly in front of the lens of your eye (we will ignore any distance between the eye’s l ens and the corrective lens). Where should the corrective lens form an image of the moon, and what kind of image is it? e. Determine the focal length of the corrective lens needed to see the moon clearly. Is the sign of your answer consistent with part c? 4. The condition of hyperopia (far- sightedness) can arise when the distance between your eye’s lens and retina is smaller than appropriate for the range of focal lengths of your eye lens. Suppose that the distance between your lens and retina is actually 1.62 #$ but the minimum and maximum focal lengths of your lens are the same as in problem 1. a. Using the appropriate focal length, what is the near point of your vision in this condition? How does this compare to the near point of normal vision, 25 #$ ? b. When you hold this page 25 #$ in front of your eye, it appears blurry. Where is the image of the page created by your eye lens located? Is it in front of or behind your retina? c. What sort of corrective lens do you need to see the page clearly when it’s 25 #$ in front of your eye? Explain how you can tell. This study source was downloaded by 100000817901397 from CourseHero.com on 11-30-2023 08:49:33 GMT -06:00 https://www.coursehero.com/file/43266418/Discussion-12-worksheet-2-SOLUTIONSpdf/

d. Suppose you place the necessary corrective lens directly in front of the lens of your eye (we will ignore any distance between the eye’s lens and the corrective lens). Where should the corrective lens form an image of the page when it’s 25 #$ in front of your eye, and what kind of image is it? e. Determine the focal length of the corrective lens needed to see the page clearly when it’s 25 #$ in front of your eye. Is the sign of your answer consistent with part c? This study source was downloaded by 100000817901397 from CourseHero.com on 11-30-2023 08:49:33 GMT -06:00 https://www.coursehero.com/file/43266418/Discussion-12-worksheet-2-SOLUTIONSpdf/ Powered by TCPDF (www.tcpdf.org)