Physics Review Question Unit: Optics Year: 1991 Question#: 97 Question: Base your answers to questions 97 and 98 on the diagram at the right which represents a convex lens being used to form the image of an object. The distance from the center of the lens to the object is 0.060 meter. The distance from the center of the lens to the image is 0.120 meter. If the height of the object is 2.6 x 10-2 meter, the height of the object is (1 ) 1.3 x 10-2 (2 ) 2.0 x 10-2 (3 ) 2.6 x 10-2 (4 ) 5.2 x10-2 What is this question really asking? Explanation by: Jaques S. [ Return to question menu ] Answer 1 Incorrect. This answer assumes an inverse porpotion of height to distance. return to top Answer 2 Incorrect. This answer is based on the assumption that since the difference between the distances of the object and the image is 0.06 m, the difference in heights of the object and the image is .06 m. return to top Answer 3 Incorrect. The image height would be the same as the object height if the image and the object were the same distance from the lens. return to top Answer 4 Correct. The height of the object devided by the distance from the center of the lens equals the height of the image devided by its distance from the center of the lens (So/Si = do/di). Since the image distance is twice the object distance, the image's height is twice the object's height. return to top What's this question really asking? How do you find the height of an image? return to top
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