Question

The answer to 6a is 4 cm or 12 cm. The answer to 6c is 1.5 cm or 13.5 cm. I just do not know HOW to get the answer to a, b, or c.

PHYS 122 Test 3 Wed, 4/6/16 6. (20 pts) An object is placed 38.5 cn fromi a screc. Two lenses are placed between the object and the screeu. Tst les (focal length of 5.0 cn) is 15.0 cu fron the object and the secoud kens (focal length 3.0 em) is between the first lens and the screen. (a) Find one location of the second lens (distance between it and the screen) so that the set up foru is an ?lllage on the screen. (h) Draw two clear ray diagranus (using the graph paper on the back side of this page contirning that the setup forns an image at the desired location. Each diagram should iuvolve only one lenis, and should include at least two principal (special) rays. (c) If the original object is 9.0 em hig, how high is the image on the screen? Is it inverted or upright with respect to the original object? Complete Clea5 PlausibleI Correet8 20

Answer 1

dos rightarrow distance between object to first lens F_1 f_1 rightarrow focal length of F_1 f_2 rightarrow focal length of F_2 di_1 rightarrow distance to image created from the first lens d o_2 rightarrow distance to object for second lens di_2 rightarrow distance to screen from second lens to determine the image distance for the first lens F_1 f_1 = 5.0 cm do_1 = 15.0 cm di_1 = ? (2) from the lens eqn 1/f_1 = 1/do_1 + 1/di_1 1/di_1 = 1/f_1 - 1/do_1 = 1/s - 1/15 -= 2/15 di_1 = 7.5 cm the first image located at 7.5 cm behind the first lens. So the distance between the image to screen is 38.5 - (15 + 7.5) = 16cm let the distance between f_2 and the object is x as then lens to screen distance (16 - x) cm the lens eqn f_2 = 3 cm u = x cm v = (16 - x) cm