Find the focal point of the lens according to the measuring data.

In this experiment, we measured the focal length of a thin lens by using displacement method. If the distance between the object and the screen is at least four times of the focal length and when we move the lens, we can get a clear image twice at different points as shown in Figure 2. Thing the conditions D=s, +3, -s, +2j-s, -s +d.s, - s; +d. we can get the formula D matic of thin lon bringing AD Experiment setup LEPO-54-2 LEPO-54-3 LEPO-54-4 LEPO Figure 2-1 Photo of experimental setup Figure 2-2 Configuration of components Experimental Procedures: 1) Refer to Figure 2-2, align all components in same height along the optical mail; 2) Move lens & back and forth, till a clear magnified image of object on P is observed on screen //. Write down the positions of object P. lens L, and image screen # as Di, h and Du, respectively. 3) Fix Pand If, move long & far away from P till a clear minaSed image is observed on /. write down position of lens & as dis 4) Reverse L. repeat steps 1-3, obtain another two locations of lens [ as dy and di; 5) Calculate focal length as: 1, _ (D. -D)' -(d. -d) 4(D, - D) 1 (D. - D) -(d, -d,) In this experiment, we move lers L. back and forth till a clear magnified image of object on P is observed on screen H. Write down the positions of object P, lem 1., and image screen Has Dy. th and Dy. respectively. The position of P is shown below 4 5 6 7 8 9 801 2 3 0 901 2 asition of L. is shoem below: 234 5 6 7 8 3 501 2 38 9 601 2 3 4 5 6 71 The position of H is sheran below: 7 8 9 101 2 34 Fix P and H. nove less L far away from P till a clear misified inage is observed on H. write down position of leas L. as da The position of I. is shown below: 4 5 6 7 8 9 23 6 7 8 9 401 2 Reverse L, repeal the same steps above and obwin another two locations of less L as dy and da is sharan helia: 7 8 9 501 2 3 601 2 3 4 4 5 6 7 8 9 6 7 8 9 401 2