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OPTICS (OPTO 251) LECTURE FORMAT Lecturer SAFIAH. H. MULLA, MSc, OC(C), Bsc (OPTOMETRY) Optometry Department College of Applied Medical Science King Saud University P.O. Box 10219 Riyadh, 11433 Tel: (01) 4355010 / 107 E-Mail: [email protected] Office Hours: By appointment. Hours of Work: Saturday to Wednesday -8.00 a.m. - 2:00 p.m. Class Description: In many ways the perceptual processes of vision are abstract and inexplicable; however, image formation, which is critical to the visual process, is governed by concrete physical criteria. This class will analyze physical and optical principles, with an emphasis on the measurement of light and on its behavior in image formation. Geometrical optics in physical modalities will be investigated critically in experimental and clinical venues. This class is a prerequisite for Ophtalmic Optics I (OPTO 253), Visual Optics (OPTO 273), Contact lenses I & II (OPTO 354 & OPTO 355), and Physical Optics (OPTO 356) This class meets for two hours each week. There are three 1-hour laboratory sessions. Educational Objectives: Through lecture, discussion, group activity and given clinical scenarios, this class will provide the student with the knowledge and practical application of that knowledge so that the student will show the following understanding and abilities: 1. The student will be able to solve optical problems in experimental and clinical settings, regarding the behavior, management, and manipulation of light, and image formation. 2. The student will be competent in the biomedical application of instrumentation used in light measurement. S.Mulla, 2008 1 Syluboulls: - - - - - Light physical properties electromagnetic spectrum sources Light behavior absorption transmission: Beer-Lambert Law scattering reflection internal (total)reflection ray diagram & image formation refraction Snell’s Law critical angle diffraction interference Manipulation of light diffusion lenses concave lenses convex lenses ray diagram image formation mirrors concave mirrors convex mirrors image formation magnification ray diagram internal transmittance prisms vergence image formation magnification ray diagram multiple lenses & telescope S.Mulla, 2008 2 Resources: Additional reading: - Hunter, D.G. and C.E. West. Last Minute Optics: A Concise Review of Optics, Refraction and Contact Lenses. Thorofare, NJ: Slack, 1996. Stoner, E.D. and P. Perkins. Optical Formulas Tutorial. Boston: ButterworthHeinemann, 1997. Carpenter Roger H.S. and J.G. Robson. Vision Research: A Practical Guide to Laboratory Methods. New York: Oxford University Press, 1998. Rubin, Melvin L. Optics for Clinicians. 25th Anniversary ed. Gainesville: Triad Publishing, 1993. Other readings assigned by the instructor. Assessment: Laboratory assignments: 3 laboratory reports (5% each) 15% Mid-Term Examination: 2-3 hour, short answer, MSQ and detailed problem solving 25% Students perform individually and are graded by comparison to established standards 10% Final Comprehensive Examination: 3-hour, short answer, short problems and essay (detailed problem solving) 40% Class Participation: Students will be graded on their ability to answer questions in class from the material of previous classes. 10% S.Mulla, 2008 3 OPTO 251- MOCK EXAM: 1. There are two good ways to find a description of an image in a lens. One is to use the thin lens equation. The other is to use A. B. C. D. Snell’s law. The law of refraction. A free-body diagram. A ray diagram. Answer: D 2. A luminous object that is 4.0-cm high is placed a distance of 45.7 cm from a double convex lens having a focal length of 15.2 cm. Determine the image distance and the image size. Answer: We know that: h o = 4.0 cm do = 45.7 cm f = 15.2 cm We need to determine: d I and h i We can use the lens equation to determine the image distance. 1/f = 1/do + 1/d i 1/ (15.2 cm) = 1/(45.7 cm) + 1/d i 0.0658 cm-1 = 0.0219 cm-1 + 1/d i 0.0439 cm-1 = 1/d i S.Mulla, 2008 4 3. The visible region of the electromagnetic spectrum extends from about ________ up to about _________ A. B. C. D. 10.0 nm ; 75.0 nm 220 nm ; 530 nm 400 nm ; 700 nm 900 nm ; 12,500 nm Answer: C 4. The critical angle is the angle of incidence beyond which A. B. C. D. All light energy is absorbed. The frequency of the light approaches zero. All incident light is reflected. The medium of incidence becomes transparent. Answer: C 5. If parallel light rays strike a + 4.00D lens, where will the image be? Answer: Parallel light has no vergence. Therefore, using the equation U + D = V U = vergence of object at the lens = 0.00D D = lens power = + 4.00D Vergence of image rays = V = 0.00D + (+4.00D) = +4.00D. Converting to centimeters, 100cm/+4.00D = +25 cm to the right of the lens. S.Mulla, 2008 5 7. Find the angle of refraction r for the following diagram. air glass r=? i = 25 n = 1.5 Answer: Snell's law gives: sin i n sin r Rearranging: sin r sin i n Substituting in values: sin r sin 25 0.423 0.282 1.5 1.5 To get sin 25 degree use the sin button on your calculator. r arcsin 0.282 16.4 Here, you use the unfortunately named sin–1 button on your calculator – usually inv and sin buttons. (We say ‘r is the angle whose sine is 0.282' or ‘r is arcsin 0.282'.) S.Mulla, 2008 6