Optics Lab - lab assignment PDF

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Name: Tianna Fredericks Experimental Title: Exploration of Mirror Reflection and Lens Refraction Experimental Objective: Observe and understand how tracing of paraxial rays can be used 1 to determine quantitative image characteristics, such as focal length using f = R , 2 height, radius of curvature, and location. Construct graphical illustrations of mirrors (concave, convex) and lens (converging, diverging) and consider relationships that may do ho = . relate characteristics using the formula d i hi Experimental Procedure: 1. Obtain quad-ruled paper for analytical drawings. Begin by drawing the mirror or lens in use. (Concave curves inwards, convex curves outwards, converging lens is thick in the center and curves on both sides, and diverging lens is thin in the middle and causes parallel rays to diverge). 2. Begin each illustration by drawing principal axis. (If necessary, insert scale bar for reference). 1 3. Insert the focal point, F, using the following formula f = R , where R equals 2 radius of curvature. Focal point will be positive for concave and converging lens and negative for convex and diverging lens. 4. Insert radius of curvature, C, according to the given distance. 5. Insert the object according to the given height. 6. Draw the following rays according to the mirrors/lens in use: a. Concave Mirror: 1) Ray parallel to principal axis that reflects from mirror and passes through F, 2) Ray that passes through F and after reflection from mirror, travels parallel to principal axis, 3) Ray that passes through C and reflects back on itself after striking mirror b. Convex Mirror (focal point should be in front of convex mirror): 1) Ray drawn parallel to principal axis reflects from mirror and appears to originate from the focal point behind the mirror, 2) Ray that heads in the direction of F but after reflection from mirror, travels parallel to principal axis, 3) Ray travels towards C but reflects back on itself after striking mirror c. Converging Lens (should be 2 focal points equidistant from lens): 1) Ray travels parallel to principal axis but after refraction, travels through F on the lens right side, 2) Ray travels through F on the left side and after refraction, travels parallel to principal axis, 3) Ray travels through center of lens without bending d. Diverging Lens (should be 2 focal points equidistant from lens): 1) Ray travels parallel to principal axis and after refraction, appears to originate from F on left side, 2) Ray travels from objects towards F on right side but after refraction, travels parallel to principal axis, 3) Ray travels through center of lens without bending

7. Insert image (using colored pencil to distinguish) where paraxial rays appear to intersect after traveling from object and reflecting from mirror/lens. 8. Measure image height and distance from mirror/lens. Data/Results: Analytical Illustrations Concave Mirror

Convex Mirror

Converging Lens

Diverging Lens

Image Characteristics Image data Real/Virtual #1 Concave Mirror Real #2 Convex Mirror Virtual #3 Converging Lens Virtual #4 Diverging Lens Virtual

Upright/Inverted Inverted Upright Upright Upright

Distance (in) 1.25 0.8125 6.1875 1.3125

Height (in) 0.343 0.343 4.25 0.375

Conclusion: Based on the formula used to find focal length for each mirror/lens, the radius of curvature 1 is positive for concave and converging lens. Using the formula f = R , this results in a 2 positive focal point. However, the radius of curvature is negative for convex and diverging lens, which results in a negative focal point. Based on the ray-tracings used to determine image characteristics, concave mirror produces a real image that is inverted relative to the object. However, this does not always hold true as concave mirrors can also produce virtual/upright images depending on the location of the object, such as if it is located beyond the radius of curvature or beyond the focal point, F. Similarly, depending on where the object is located with respect to the lens, a converging lens can form either a virtual or real image as well. On the other hand, a convex mirror, no matter where it is placed in front of the mirror, always forms a virtual, upright image. Likewise, a diverging lens will also always form a virtual, upright image.

do ho = relates the distances of object (do) and image (di), d i hi respectively to the heights of the object (h o) and image (hi). This means that the ratio of the distance of the object to the lens to the distance from the image to the lens is equal to the ratio of the height of the object to the height of the image. Although a ruler was used for this experiment, this relationship could also be used to determine quantitative values such as image height, image distance, etc., by plugging in known values to solve for the unknown. Additionally, the equation...