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(33%) Problem 2: A convex lens is placed a distance D = 12.0 cm in front of a projection screen for the purpose of imaging objects that are a great distance away, but the images appear at an image distance di =6.25 cm which falls short of the screen. L D Due to the supporting structures holding the lens and the screen, they may not be easily relocated. A student corrects the problem by placing a concave lens with a focal length F= -8.25 cm a distance L in front of the first lens. $ 20% Part (a) Without the addition of the concave lens, an object placed at a distance de in front of the convex lens would result in an image focused on the screen. Using the values given in the problem statement, calculate the value of do- d. -- 12.98 Feedback: is available. d. = -12.98 X Incorrect! 20% Part (b) The student knows that the image of the concave lens should serve as the object of the convex lens. If the concave lens has the focal length given in the problem statement, at what distance L in front of the convex lens should it be placed? L = 4.79 ✓ Correct! A 20% Part (C) Suppose that an object is placed not at infinity, but it is located do,1 =1.7 m to the left of the concave lens. Calculate the image distance, di 1. for the image of the first lens, relative to the position of the first lens, including the sign consistent with standard sign conventions. A 20% Part (d) The image of the concave lens becomes the object of the second lens, the convex lens. Calculate the position of the object for the second lens, do,2. This position is specified relative to the convex lens and must include any sign consistent with sign conventions. 4 20% Part (e) Calculate di2, the image position of the second lens, the convex lens, relative to the second lens. It should be pretty close to but not exactly at the position of the screen. Be certain that the your answer includes any sign consistent with the sign conventions. Grade Summary di 2 = cm Deductions Potential 100% 096