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n, Ee, =z 1. | Reflection of light 1, = 2. Plane mirror 2, 2 8. | Spherical mirrors 6, - 4, Refraction of light 16, a 5. Total internal reflection 19, 4 6. Refraction at curved surfaces | 22, s ai Lens | 25, E 8. Combination of lens & mirrors 33, 5 9. Chromatic aberration 35, QO 10. Prism 36, Zz 11. | Dispersion of light 40, ' 12. | Optical Instruments 42, o [Simple microscope, Compound microscope,, - Telescope, Lens - Camera], o 13. _ | Defects of eves 48, = 14. | Natural phenomenon of sunlight 49, a 15. | Exercise-I (Conceptual Questions) 52, 16. | Exercise-II (Previous Years Questions} 60, 17. | Exercise-III (Analytical Questions) 66, E 18. | Exercise-IV (Assertion & Reason) 68, , , , , , , , , , , , NEET SYLLABUS, , Reflection of light, spherical mirrors, mirror formula. Refraction of light, total intemal reflection and Its applications, optical fibres, refraction at spherical surfaces. lenses, thin lens formula, lens-maker's formula. Magnification, power, of alens, combination of thin lenses in contact combination of a lens and a mirror, Refraction and dispersion of light, through a prism. Scattering af light- blue colour of the sky and reddish appearance of the sun at sumrise and sunset, Optical instruments: Human eye, image formation and accommodation, correction of eye defects (myopia and, hypermetropia) using lenses. Microscopes and astronomical telescopes {reflecting and refracting) and their magnifying, powers,

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WILLEBRORD VAN ROYEN SNELL (1580 - 1621), , Though, there isno definitive record regarding the date of birth of Willebrord, van Royen Snell but, it is believed that he was born in Leiden in around, 1580.Willebrord van Royen Snell was a prominent mathematician and, astronomer. His name and works had been associated with the law of, refraction for centuries in the west. However, later it was discovered that the, law was actually formulated by Ibn Sahl and that Snell only rediscovered it., Snell was a mathematical genius and developed a new method to calculate, the mathernatical function, ‘PY .which brought about a significant development, in the field of mathematics. He made several theories on the law of, refraction, on the basis of the work which he rediscovered in 1621. Snell also, published various works that defined new boundaries in mathematical and, scientific research. Snell travelled extensively all around Europe to study and discuss astronomy. Here, he, collaborated and worked with some of the best minds in the field of astronomy, such as Johannes Kepler and, Tycho Brahe, According to certain historical accounts, Snell strongly criticized the works of Aristotle and, Copemicus and stated that their works would lay a negative impact on science if other astronomers and, scientists followed then with so much reverence. However, he did believe in the theory of the earth's centered, system and agreed with the works of Ramus. In 1626, atthe age of 46, Snell passed away from a condition, called ‘colic’, which paralyzed his arms and legs., , , , DR. NARINDER SINGH KAPANY, , Bor at Moga in Punjab (India)on 12 October 1926 and educated in England,, Dr. Narinder Singh Kapany has lived inthe United States for forty-five years., A graduate of Agra University in India and received his Ph.D. from the, University of London in 1955. Dr. Kapany is widely acknowledged as the, father of fiber-optics. His research and inventions have encompassed fiberoptics communications, lasers, biomedical instrumentation, solarenergy and, pollution monitoring. He has over one hundred patents, and wasa member, of the National Inventors Council. He has received many awards including, ‘The Excellence 2000 Award trom the USA Pan-Asian American Chamber, of Commerce in 1998, In 1960, he fourxded Optics Technology Inc. and was, Chairman of the Board, President, and Director of Research for twelve, years. Dr. Kapany has published over 100 scientific papers and four books on opto-electronics and, entrepreneurship. He has lectured to various national and international scientific societies. He is also trustee, of the University of California, Santa Cruz Foundation and the Menlo School in Menlo Park, California. As, an artist, Dr. Kapany has created 40 “dynoptic” sculptures which were first displayed in a one-man show at, the Exploratorium of the Palace of Fine Arts in San Francisco in 1972, Since then, the collection has been, viewed at museums and art galleries in Chicago. Monterey. Palo Alto, and Stanford. Dr. Kapany lives in the, Bay Area with his wife, Satinder. His son, Rajinder, is a hi-tech executive; and his daughter, Kiren, is an, attomey and filmmaker

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RAY OPTICS AND OPTICAL INSTRUMENTS, , INTRODUCTION, , Optics is the branch of physics which deals with the behavior of light waves, Under many circumstances, the, wavelenath of light is negligible compared with the dimensions of the device as in the case of ordinary mirrors, and lenses. A light beam can then he treated as a ray whose propagation is governed by simple geometric rules., The part of optics that deals with such a phenomena is knawn as geometrical optics., , PROPAGATION OF LIGHT, Light travels along straight line path in a certain medium or in vacuum. The path of light changes only where, the medium changes, We call this rectilinear (straightine) propagation of light, A bundle of light rays is called, a beam of light., , , , . Apart from vacuum and gases, light can travel through some: liquids and solids aswell. A medium in which light, can travel without attenuation over large distances is called a transparent medium, Water, glycerine, glass and, clear plastics are transparent. A medium in which light cannot travel is called opaque. Wood, metals, bricks., elc., are opaque. In materials like oil, light can travel some distance, but its intensity reduces rapidly, Such, materials are called translucent., , REFLECTION OF LIGHT, , When light rays strike the boundary of two media such as air and glass, a part of light bounces back into the, same medium. This phenomenon of light is called Reflection of light., , () ~~ Regular / Specular reflection :, When reflection takes place from a perfect plane surface, , then rays remain parallel after reflection It \s called Regular reflection., , , , (i) Irregular / Diffused reflection, When the surface is rough, light is reflected from the bits, , of its plane surfaces in different directions. This is called Irregular * A 7 so x C, reflection, This process enables us to see an object from any position. , LAWS OF REFLECTION, , . Incident ray, reflected ray and normal at the point of, , incidence all lie in the same plane., , The angle of reflection is equal to the angle of incident ie. 4 i= 71., , , , Fy Oars racer ncuciue wor wr omcsao once RENEE! NEON:

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REAL AND VIRTUAL SPACES, A mirror, plane or spherical divides the space into two regions ;, (a) Real space, the side where the reflected rays exist., (b) Virtual space is on the other side where the reflected rays do not exist., , Real Virtual Rot fa Virtus!, Space Space space B epace Riel vad, , qoce & quer, , OBJECT, , Object is decided by incident rays only. A point object is that point from which the incident rays actually, diverge (real object) or towards which the incident rays appear to converge (virtual object)., , , , a is decided by reflected or refracted rays only. A point image is that point at which the refracted /, reflected rays actually converge (real image) or from which the refracted /reflected rays appear lo diverge, (virtual image)., , , , °, (Real image), , , , REFLECTION FROM PLANE MIRROR, A plane mirror is a mirror with perfectly plane reflecting surface., Plane mirror is the perpendicular bisector of the line joining object and image., , . The image formed by a plane mirror suffers lateral-inversion, |c., left is tumed Into right and vice-versa, with respect to object in the image formed by a plane mirror ., , loft Might right tele, , R\wi &, , , , FIR cancer siewormnncrvcrie 0 ter necnasecenr Par mANeS MECH

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Fy Oars rece ncuciue wor er omcsooncR REBEL! MOEN, , a Pre-Medical : Physics, , , , When a wall clock is placed in front of a plane mirror then the, clock is the object and its time is object time and the image of, the clock is observed by a person standing in front of a plane, mirror then time seen by him is as follows., (i) = Object Time ~ Al’, , Image Time = 12 - Al ), (i) Object Time = A" B¥, , Image Time = 11 - 60'- A" B®, (ii) ~~ Object Time = A" BMC*, , Image Time = 11 - 59'- 60" - A"BNC®, , , , A plane mirror behaves like a window to a virtual world., , ee, naituel Sa w, , To see the complete image in a plane mirror the minimum length of plane mirror should be half the height of, a person., , , , , , , , , , Ne nS, , , , , , From figure. AHINM and AENM are congruent ——— 1K % M, 1 nt, -EN =HN + MD = EN = SHE —, Similarly AEN’ M' and ALN’ M' are congruent h |, 2—N=NL 9. MD«EN= i FL. a 7 al, i, Length of the mirror MM'= MD + MD = 5 HE + pel i, , - PIHE + EL) ~ 3 HL, -. Minimum length of mirror is just half the height of the person,, . This result does not depend on position of eve fheight of the eye from ground)., . This result is independent of the distance of person from the mirror., , H, Deviation for a single mirror 6 = 180 - (i + rh; Zi = 41; 6 = 180-2: ‘e, us, , Total deviation produged by the combination of two plane mirrors, which are inclined at an angle 6 from each other., , 6~6,+6, -180-20+ 180-28 - 360-2 (a+) -.l), From AQAB, 6+90-a+90-fP=180 >6=-a+8 _.(i), Putting the value of 0 in (i) from (ii), 6 = 360 - 20, , , , If there are two plane mirrors incined to each other at an angle @ the 2° number of images (n) of a point object formed are determined as follows. 4, , —_—_—SSX;:;:s 3