Lenses and Mirrors Lenses and mirrors Objective The objective of this experiment is study and understand the characteristics or features of mirrors and lenses and closely examine the produced images. Introduction This laboratory experiment analyzes the physical configurations of mirrors and lenses. The major experiment components include image screen, the object and optics device which are placed in such a way that they can be easily repositioned. The components’ positions are determined using a meter stick. When light from a particular source passes through a lens with the resulting image being focused on a screen. Both mirrors and lenses have the focal length, f, as a common characteristic. The focal length is defined to be the distance of the image for an object that is considered to be infinitely positioned. (Jerry D. Wilson, 2014) Theory The geometry analysis of diagrams for mirrors and lenses that provides a mathematical relationship between the image position (s’), the object position(s) and the focal length(f). These characteristic quantities are obtained from the lens or mirrors’ surface and the formula is as shown below: 1/s + 1/s’ = 1/f 3 Lenses and Mirrors It is worth noting that the above formula is applicable to all thin lenses, mirrors and all image types. However, in the case of spherical mirrors, the radius of curvature is two times larger than the focal length. on the other hand, lens or mirror magnification is obtained as follows: h’/h = s’/s where h' is the image height and h is the object height. The figure below demonstrates the experiment: The figure indicates the distance of the object(p) and the distance of the image (q) both of which are measured from the lens center. The image height is indicated by h’ while the object height is h. (Neena Sinha, 2002) Procedure The experiment is set up as shown below. The position of the slit plate lens is adjusted such that a ray parallel to the table is obtained. The experiment is done in three parts as illustrated. 4 Lenses and Mirrors Results 5 Lenses and Mirrors Lens Focal Length (cm) Measured Distances (cm) Measured Heights(cm) Magnifications Focal Length (cm) or DIREC T OBJEC T IMAG E OBJE CT IMA GE DISTAN CES HEIGH TS CALCUL ATED Mirr or fdirect ± o ± i ± O ± I ± m = i/o ± m = I/O ± fcalc A 18 0 23 0.1 # 0.1 3. 4 0. 1 4. 5 0. 1 1760.2 15. 3 18 A (rev) 77 0.1 # 0.1 3. 4 0. 1 1. 1 0. 1 1797.8 3.7 4 18 B 9.5 0 11 0.1 # 0.1 3. 4 0. 1 2 7 0. 1 1010 91. 8 10 B (rev) 22 0.1 # 0.1 3. 4 0. 1 0. 7 0. 1 1687.8 2.3 8 17 B+C 24.3 0 33 0.1 # 0.1 3. 4 0. 1 7. 5 0. 1 2193.8 25. 5 22 B+C (rev) 33 0.1 # 0.1 3. 4 0. 1 1. 8 0. 1 2211 6.1 2 22