SSBsir Physics-Ray Optics Assignment PDF

(PHYSICS) GPS YUVODAYA nnstorooing Inac The to...

(PHYSICS) GPS YUVODAYA nnstorooing Inac The to usb yero XI1CBSE(GR- ALLJ RAY OPTICS AND OPTICAL INSTRUMENTS SHORT QUESTIONS:- Mark 1 MCQS 1. A ray of lightstrikes a silvered toanotherone surfaceinclined at an angleof 90'Then thereflected ray will turn through M (a) o (b) 45 (c) 90 (d) 180" 2. If thereflected image formed is magnifiedandvirtual, then the mirror system is (a)concave only (b) convex only (c) plane (d}concaveor convex A compound microscopeconsistsof an objective lenswith focallength1.0cm and eye pieceof focallength2.0 cm anda tubelength20 cm the magnification will be (a) 100 (b)200 (c) 250 (d) 300 4. A converginglensis used to form an imageon a screen.When the upper halfof the lens is coveredby an opaque screen, a)halfthe image willdisappear (b) completeimage willdisappear (c) intensity of image will decreases (d) intensityof image will increases. 5. A compound microscope consistsof an objectivelenswith focallength1.0cm and eye pieceof focal length2.0 cm and a tube length20 cm themagnification will be (a) 100 (b)200 (c)250 (d) 300 6. A converginglens is used to form an image on a screen. When the upper halfof the lensis coveredby an opaque Screen (a)halftheimage willdisappear. (b) incompleteimage will be formed. (c)intensityof image will decreasebut completeimage isformed. (d) intensityof image will increasebut image is not distinct. 7. Inopticalfibres, therefractive index of thecoreis (a)greaterthan that of thecladding. (b)equal to thatof the cladding. (c)smaller than thatof the cladding. (d) independentof thatof cladding. 8. An objectis placedat a distance of 0.5m infrontof a plane mirror. The distancebetween object and image will be (a) 0.25 m (b) 0.5m (c) 1.0m (d) 2.0 m 9 Airbubble in water behavesas (a) sometimes concave,sometimes convex lens (b) concave lens (c) convex lens (d) alwaysrefracting surface 10.We combine two lenses,one is convex and other is concave having focal lengths f(1) and f (2)and their combined focallengthis F. Combination of the lenseswill behavelike concavelens,if (a) f,> fa (b) f; = f; (c)f< f (d) f; n, and (ii)ng A dot is made d,> d,and refractive indices at the bottom of the , isequalto theangleof theprism.Findthe angleof the >>Ha are put in a beaker. Ihe beaker.For near normal vision, tindthe 21.Show that for a materialwith refractive index 2V2.lightincident at any angleshallbe guidedalong a length perpendicularto the incident face Z2. In the followingdiagram,an object'0' is placed15 cm in frontof a convex lensL, of focal length20 cm and the finalimage is formed of 80 cm from the secondlensL,Findthe focallengthof the lens L. at I ata distance 20cm 80cm 15cm Ly 23. Usingtheray diagram for a system of two thetwo lenssystem can be regardedas equivalent to a singlelensof focallengtht, where 11 lensesof focallengthsf; and f in contactwith each other,show that 1 Alsowritetherelation power of the lenscombination. for theequivalent 24. Determine the positionof theimage formed by the lenscombinationgivenin thefigure. J10., -10 +30 cm 30 cn cin0 25.A ray PQ incidentnormalyon the refracting intheprism BAC made of materialof refractive faceBA is refracted index1.5. Complete the path of ray through the prism.From which face will the ray emerge? Justifyyour answer. 26. (a) Writetwo necessaryconditions for totalinternal reflection. (b) Two prismsABC and DBC are arrangedas shown in figure. anglesfor the two prismswith respecttoairare41.1" The critical and 45° respectively. Trace the path of the raythrough thecombination. 27.Figureshows a ray of light passingthrougha prism.If the refracted rayQR tothebase is parallel BC,show that () ==A /2, YuvodayaCBSE, Balangir-Connect: 06652-230136, 9437367867/9777884488  ) angel of minimum deviation, , 2-A 28. A ray of lightis incident on a prism at an angleof 45tand passes symmetricaly as shown in thefigure, Calculate. (a) the angleof minimum deviation, (b) therefractive index of thematerial of the prism,and (c)the angleof refraction atthepoint P. 29. Three rays(1,2, 3) of differentcolours fall normally on one of the sidesof an isosceles rightangledprism as shown. The refractiveindex of prism for theseraysis 1.39,1.47and 1.52respectively.Findwhich of theserays getinternally reflected and which get only refracted from AC. Tracethe paths of rays. Justify your answer with thehelpof necessary calculations. 30. The figureshows a rayof lightfalling normallyon the faceAB of an equilateral glass prismhaving refractive index 3 placedin water of refractiveindex Will this ray suffertotalinternalreflection on strikingthe face AC? 2' Justifyyour answer. 31.A ray of lightpassing from airthrough an equilateral glassprism undergoes minimum deviationwhen theangle of incidentis % of the angleofprism.Calculate intheprism. thespeedof light 32. (a) Draw a ray diagramfor theformation of image by a compound microscope. (b) You aregiventhefollowingthreelenses. to Which two lenseswill you use asan eyepieceand as an objective constructa compound microscope? Lenses Power (LD) Aperture(em) 6 Lg 10 33.Drawa ray diagram to show how the finalimage is formed at infinity in an astronomical refractingtelescope. Obtainan expression for itsmagnifyingpower. 34. Draw theimage,when an objectis placedbetween the focus and pole of a convex lens. 35. An illuminatedobjectand a screenareplaced90 cm apart. Determinethe focallengthand natureof the lens requiredto produce a clearimage on the screen,twicethe size of the object. 36. Findtheequivalent focallengthof the combination of lens. Yuvodaya CBSE,Balangir-Connect:06652-230136, 9437367867/9777884488  Blass Blass Water 37. With the help of a ray diagram explainthe working of a reflecting telescope. Mention two advantagesot a reflecting telescope over a refracting telescope S8. A symnmetricbiconvexlensof radiusof curvatureR and made of glassof lndex 1.5,s refractive placedon atayer oT liquid placedon topofa plane mirroras shown inthefigure. An opticalneedlewith itstip on theprincipalaxis oT theens ismoved along theaxs untilItsreal,invertedimage coincides with the needleitself. The distarniceot the needlefrom the lensis measured to be x. On removing theliquldlayerand repeatingtheexperiment,the distanceisfoundtobe y.Obtaintheexpression for therefractive index of theliquid in termsof x and y. (2018) LONG QUESTIONS : 5 Marks each An objectis placedin front of a concave mirror.It is observedthata virtualimage is formed. Draw the ray 1. diagram toshow theimage formationand hence derivethe mirror equationA 111 2. Derivelensmaker'sformulafor a biconvex lens. (a) the principalaxis of a convex lensof focallength 10 cm. A (b) A pointobjectis placedat a distanceof 12 cm on If thefinalimage coincides Convex mirroris placedcoaxially on the other sideof the lensat a distance of 10 cm. focal length of the convex mirror. (2020) with the object, sketchthe ray diagram and findthe objecton the principalaxis of a spherical 3. Draw a ray diagram showing the formationof the image by a point indices njand n, when a point source is kept in rarermedium Convex Surfaceseparating two media of refractive and image distance in terms of refractive index of the index n,. Derivethe relation b etween object of refractive medium and radiusof curvatureof the surface. formulainthe case of thinconvex lens. (Delhi2014C) Hence obtainthe expression for lens-maker's compound microscope at least image by a 4. (a) Drawa labelled ray diagram showing the formationof a final distanceof distinctvision. produced by theeye (b) The totalmagnification produced by a compound microscopeis 20. The magnification and eyepiece certainobject.The distancebetween the objective pieceis 5. The microscopeis focussedon a of the objective calculate the focallength is observed to be 14 cm. If leastdistance of distinctvisionis 20 cm, and theeye piece. telescope. is formed at infinityinan astronomical refracting 5. Draw (0) a ray diagram to show how the finalimage Obtainan expression for itsmagnifyingpower. L, a concave lensof focallength L beinga convex lensof focallength24 cm and (i0) Two thin lensesLy and L,, in front of the lens at a of 45 cm. A 1 cm tallobjectis placed L at a separation 18 cm are placedcoaxially heightof theimage formed by the combination. distance of 36 cm. Findthe locationand 4 to water. Given ugw and index of glass with respect 3 : 6. (a)Findtherefractive under water. If the wavelength of (b) A source of yellowlight placedin airis observedby a person swimming colour observed by the person. wavelengthand as yellowlightinairis 6000 A, then finditsspeed, of refraction r,what is the of thickness t at an anglei with an angle ray thrOugh a glass slab (c) When a passes lateralshiftof the emergent ray? 06652-230136, 9437367867/9777884488 Yuvodaya CBSE, Balangir-Connect:  NCERT EXCERCISES: 1 A Smal candle,25 cm in sizeis placedat 27 cm in tront of a concave mitror of radius what distancefrom the mrror shoulda screenbe of curvature3o crm. At placedin order to obtain a sharpimage? Describethenatura and sizeof the inage.Ii the candleismoved closer to themirror, how would thescreenhavetobe moved A5 cm needleisplaced 12 cm away from a convex image and theagnitication, miror of focallength15cm. Givethe location the Describewhat happens as the needleismoved fartherfrom o A tank is filedwith water to a height of 12.5 themirror cm The S measUred by a microscopeto be 9,4 cm. What is apparent depth ofaneedlelyingat the botfom of thetank the refractive index of water?If water isreplacedby a of retractiveindex 1.63upto the same height.by what lquo focuson the distance would the microscope have to be needleagain? move0 To Fgures (a) and (b) show refractionof a ray in air incidentat 60 with the normal to a interface, respectively.Predictthe angleof refraction glass-airand water-ait in glasswhen the angleof thenormaltoa water-glass incidence in wateris45 with interface[Figure]. Air Glass Lir Water Water 60 45; 5. A smallbulb isplacedat the bottom of a tank containingwater to a depth of 80 SUrlacoofwater thDugh.whichlicht cm. What isthe area ot the from the bulb can emerce cut? thebulb to be a pointsource). Refractive index of water is1.33. (Consicder 6. A prism ismade of glassof unknown refractive index.A parallel The angleof minimum deviationis beam of lightis incidenton a faceof the prism. measured to be 40°.What is the refractive index of the materialof the prism? The refractingangleof the prism is 60°. If the prism isplacedin angleof minimum deviationof a parallel water (refractive index 1.33). predictthe new beam of light. 7 Double-convexlensesare to be manufacturedfrom a glassof refractiveindex 1.55, with both facesof the same radiusof curvature.What is the radiusof curvaturerequired ifthe focallength is to 8 A beam of light be 20 cm? [AI20171 convergesat a pointP.Nowa lensisplacedinthe path of the At what pointdoes thebeam convergeif convergentbeams 12 cm from P the lensis a) a convex lensof focallength20 cm and (b)a concave lensof focallength16 cm? 9 An objectof size3.0cm is placed14 cm in frontofa (SimilarDehradun 2019) concave lens ot focal length 21 cm, Describetheimage produced by the lens. What happens theobjectismoved furtheraway from the lens? if 10. What is the focal lengthof a convex lensof focallength30 cm in contact with a concave lensof focallength20 cm? Is the system a converging ora diverging lens?lgnorethicknessof the lenses. 11. compOund microscopeconsists of an otbjectivelensof focal A length2.0 cm and an eyepleceof focal length 6.25 cm separatedby a distanceof 15 cm. How far from the objective shouldan objectbe placedinorder to obtainthefinalimage at (a) theleastdistance of distinct vision(25cm),and (b) at infinity? What is the magnifyingpower of the microscopein each case? 12. A person with a normal near point(25cm) using a compound microscope with objectiveof focallength 8.0 mm and an eyepieceof focallength2.5cm can bring an object placedat 9.0 mm from the objective insharp focus What is the separation between the two lenses?Calculate themagnifying power of the microscope. 13. A smalltelescopehas an objective lensof focallength144 cm and an eyepieceof focallength6.0 cm. What is the magnifyingpower of thetelescope? What is theseparationbetween the objectiveand the eyepiece? 14. (a) A giantrefractingtelescope atan observatory has an objective lensof focallength 15 m. It an eyepieceot focallength1.0cm is used,what isthe angularmagnification of the telescope? (b) If thistelescopeisused to viewthe moon, what isthediameterof the image of the moon formedby the objective lens?The diameterof the moon is3.48X 10"m, and the radiusof lunarorbitis 3.8 X 15 Use the mirror equation to deduce that 10 m. (a) an objectplacedbetween and 21 of a concave mirrorproduces a realimage beyond 2. f [Chennal2019, Foreign2017) Yuvodaya CBSE,Balangir- Connect: 06652-230136,9437367867/9777884488 10  p) a Convex mirror always produces a virtualimage independentof thelocation of the oojea (G theVinualiiage produced by a convex mirroris (Chennai2019,Deihi 2016] and the pole. alwavs diminishedinsizeandisocatedbetween tnerocus (O) an objectplacedbetweenthepole and focusof a concave mirrorproduces virtual 16 A Small pin tixedon a tabletopisviewedfrom above from a.distanceof 50 cm.a By and enlargedimage, what distancewouio tne pin appear to be raisedif it isviewedfrom the same pointthroupha 15 cm thickglass slab neld parale to table?Refractive index of glass=15.Does the answer depend on the 17. location of theStabr (a)igureshows a cross-section pipe'made of a alassfibreof refractiveindex 1.68.ne oute of a "liaht oveno o the pipeismade of a materialof refractiveindex1.44,What istherange of theanglesof theincident rayswiththeaxiSof thepipe for which totalreflections insidethepipe take placeas shown inthe igure (b)What is the answerifthereis no outercoveringof the pipe? 18. The imageofa smallelectric bulbfixed on thewallof a room isto be obtainedon theoppositewall 3 m away by means of a largeconvex lens.What is themaximum possible focallengthof thelensrequired forthepurpose? 19. A screenisplaced90 cm from an object.The imageof theobjecton the screenis formed by a convex lensat two different locationsseparatedby 20 cm. Determinethe focallengthof thelens. 20. An angularmagnification (magnifyingpower) of 30 Xisdesiredusingan objective of focallength1.25cm and an eyepieceof focallength5 cm. How willyou set up the compound microscope?