Class 12 ray optics notes (cbse), Study notes of Physics

Download Class 12 ray optics notes (cbse) and more Study notes Physics in PDF only on Docsity! i i i INDEX [SNe | Topics Page. No- 4. Raw optics 28 Reflection off Light OL Zz. spherical Misrovs on 3B. | New Cartesian sign Canvertion ou 4.1 Mirme poroula for Cmcowe mirror OG S. Mixrow formula for Convex mirror og G. | Linen Magni ificaditon of a Sphaical — 12 ‘ mirror 7 | Practicle app lldiechinnn of sphuucal Miro} 14 Refraction L7 3, , Ragen on through a Rectangulad. qlass 12 lo. | Real olipth 4 appatent olepth apa tank 2) i.) Total internal veflection 22 12. | Application of total Internal yeflection| 24 13.| Spheucel Yefrach ng Surfaces 27 WU.) Refraction fom raver 4 clenser meclium 29 at a lonvex sphaical vefracting.. SUA fale 1G] Refraction from romwh to clenter medlium at a toncave sphudcal Ragracking Surface, 32. 1@} Refraction Pom denser ate oma medium) — By Lt Lenses ay 18.] Lens Maker's formula 338 13.1 Lests~ formula, 42. 20} Linear magnification produceel by a Aq Lens 2) Coamnaten, of fersey In Contact BS  SN DOUBTERS. THERE WILL BE NiiSTAKES. BUT WITH HARD WORK, THERE ARE NO LINE 1S. | -Tepics ‘ : et Page No: 2o.| Palsm 37 23.| clispersion of; Aight 60 24-| Scatkaing of Light és : 2s.| Eye — 68 ds 26.) Defects Qf Vision 70 27.} Simple Microscope (magnifyieg gh) 71S 28.) Cempoiund Microscope 77 23-| Astronomical Telescope : a) Bo. Ccansegesin seatope) es al Newtonian tefle eccting type. telescope ee a2.| Resdlving power. &7 33. Ver Important Quections. : | l ARAMA PE FRE THERE WILL BE OSSTACLES. THERE WILL BE | Gi) Vertex or Pele- The. \ middle point or cemtre of the Spherical mirror JA Calli vertex or poles of the mirror: Tt Us Acpsssentecl by P. ‘ . Uv) Aperture ¥ of the mivror - The cllameter M)Mz of The sphericed mirror ds cote aperture LUnroar aperture oh the. miswor: (Vv) Amgulas aperture - The angle M,CM, » subtended at C by the. by the clameter of dhe spherical mirror 4s Catllsol angular Aperdurtve Wi) Paincipal axis - Tae Athrod Aina. joining the pole. amd she comtre of Cumveture © henical mirror extendecl om bet siel cs cabled pean ci peat Odds Of the mien: vib Paincs pel Section - A sector oh the sphoricol miwDy Cut by a Plane passin thong pole amd centre © cud AA of the minor ~ Caltsl Paine po sechion of the Mirror: wii) Principal focus CF + Dt a. potnt on the. principal cs of the mirror at which rouys incicluont on athe mireor in a civechon parallel do dhe pAincipal axis actually meet or appear mivroe, do diverge atten reflection tom Hae *® Im Care. o K In Gre o OWA TAc 7 actually meet. Loheredsrir) the says after. reflection appear to diverge . Q Covvex mivroy, F us a vietueal pom, OQ Concave mixror F ts & real pot S abt vetection tam the minor Concave mirror . Convex mirror Princlpal axis Principal axis Focal i 1 “nat * The cUstence © mek cua F the pole P of the sphericod ib Pete eee foced Jang cf) ) et the miro. Pes f | New Cartesian sign Conventions - | qa.) Ai the. stances AAL measure poem [pole CRD ok Sphericet mirror: ; @) Th Astanus measurtd jn the direction inaldence op el. Faken’ as postive. and the Attoncer aAsuteol in Q clrecton opposite ato the Sareeara of nei buena. of ght axe taken as negok ve (3) Tae heights measurrs upwards and perpendiculas do the principal axis of the minor ane +akar positive. and the AeighAs LAA Wee} ownwards are Fakon as neqaki ve: Object on the left . Direction of A incident light Height : : upwards | : Distance towards cq Distance Sowmen |W} __Distance towards, {+ve) the left (-ve) the right (+ve) x x Height downwards (-ve) & Reladim between f oad R (a) Cemcave Mirror - fe Ro el BK The fecal length of a Concave mirror (is equal ae horf the vacua ef Curvature of the Mirror.’ (b> Convex Mirror - Ho Re K Focal Length of a Convex minor is equal to helty of ute racing Of Cur . Seme Important Rules  As A ABC ond AAlale ane similar, $0 Thed- A® °_.<B Ala! ~. ee — @ Agetn ah AAaP ond AA'B Pp are Aimilar, So thet- “3 AaB - PB A) B! Pa S From) 29. @D omd eq. @) we gat - ce = PB “EB! Pa @ By LAA URATG aly distances gom P, we gut- Cm = PO - PR amd ca = Pa - PB Pea PB = PS PC + PB! Pri Using New Cartesian sign Convenhons - PR = -Uu > (PB =zt+Vv 4, PC = -R, than aR =. Tt —R+V Vv ox UR - UV = -VR + UuV UR + VR = 2UV Divieing both sickes by UVR , we get | py dre Vv TG R Aye kh = 1 Tat “a the veges Vv u ft mivroy for mula . Mirror Formula for Convex Mirror - f The | Image. formed ina CONVER Miro ak ad viatual ome, erect, Ress, be. the. positio of tee dyed bat: P be thre pole , F ws the painciped focus - amd c as the centre of cumature of @ Convex Mirror oh ama aperturs, Let |Pr sf ds the foced length oma PC = R > the va dis of Cues wre. ok the mirror, AB 4A O77 object - held in foe of mirror perpendialak jo its principe Axis. A oy of LE Sstasdin A omd incident on the mires lahend aod on a jr NT 4d the principal axis 2, vetlecteol along DE- On producing back, DE appears to Come F. Amotrern Pm A incident ori the mi along AP OA vetielt along Pa such Snot mire ZAPBR = Lt = LaPG= LY on producing back. , PG meets DF at A. Therefpre it virtual? hmoge. ‘ok A: P & Ahtyd ¥ Incoeant on the minor alo AC falls Normally on the mirror and retraces bs “hat, om wetlection! This also appears sto Come from al. Bra A's p endiculars stan pemdipal axis. Theretore , A'pa! Pee lay eof | tee. fabj ect AB $e" afte reflection at he CoAvex mirror As A ABC amd LaAlo'c ane Aimilor, So thed - A = “4 ’ Se 68 — © Ale ca Agen as ARBP onc ABP are Aimilar., So - AB - PB : A’ a! PB’ —— S pom es: J) emal (2) are ged - 62 - PB. ce! Pe! —— & measuzing the all clatances pom the pole P, we cam het te — CB = PRr PC cpl = pa — PB So by eq. (B) - PBt PO. _PB — f eT = () Using New Cartesian sign conven Hens - PB=zs —-Uu, pp = +V¥ amo pc = 48 So pom e= CD nree ayer - —-u rR - UH , Rv Vv | —uUV +VR 2 -UR + Uv on VR +UR = 2Uv clivieling both sides by UVR 5 we - VR_ + UR_ rm 2uUVv ave UVR UVR ah + a i= 2 u. Vv R A 4-t 24 | u Vv f When tmage formed os virtual As Ahan in fgre HW Using Rew VContesion Sign Convert ore - Ala! =< +1 4 AB=z +0 pe = 4Vv , Peetu M4 2 m= AB = PB AB PB we grt — me to-eM 0 -u so mm da Positive. Im Come of Conver miry AA shown in figs; asin nen) Cartesian sign Convento — alo 2 +I, AR +0 pal = 4+V 5 PRs -u mal = TV 0 =u, wy) = i = -v or u J vq Sa ™m ° Positive. Note - | G) When mel, mee. yprmed a enlorgect. Uiy Wher, mKL , Image foment is climirishest. Ui) bohen) m ud positive’, image must be erect (Le. virtual) Uv > whent m de negative , image must be invertes| (ie. real) (v) Tn, Case of @ ConCave minor, mos ni fication may be pobi tive oy negedive , but in Cake Convex mirrdy 5 magnificotion Ls positive only. Practical Applicahons of Spherical Mivrors - (1) A convex miner a4 uses! as a wt ctor In Street Lemps- AS @ neasutt, the At Poon sth Lamp cliverges ever, a Longe area. Gid A Convex mivvor Us useol as Q olrivers mirror in all vehicles Like cars omd scooters letc., for Asoking ot the tboaffice ot the rear of the vehicle: Such A minor haw a much wiclr pid af view) as Companes| AD A plane mirror or a Conrav’ mirrnyr. The images fovmeel ar small and ct. Gi) A Concave minor .o used as a veflector in search Lignts 5 head Lights ‘of motor vehicles, telescope 4 Solar. cokers etc. Gv) A tencave mivvoy ws algo usecl as Q shaving mixror or make 4p mirwmv as ct Can em eseect amd magni fieol emage - e) Am object 4a blaceol 18 tm. -in nt Q mixror. eet the Rnege. ferred! at 4 oe +o 1 a the mirror, Calculate abs focod » Ts the InOY Convex or concave ? what +s the nedurac fs the. image: 2 What +s the yaous of Curvotuar of the mirror ?, , Ss). Herz Us 18cm. > we Ucm. ‘5 1. + tars LL Ae J ft vo u Joel ol 2 Z f 4 18 AG So foe B6/q = S14 Cm, As focel Lingty is positive , tha mirror must be Conver, The Image ig virtiel, Erect omd smaller in size. Also Rc 2¢ = 2xe-ly = fo2ecm:, : malt candle 2° Cm im size. is lacecl 27¢m- Se, yond G Ee mirror of soclius fi Curvature 36 Yer AK what Hastanw the mire shold a scytern be places! in ovles td recaive a shevp image * Describe the notuac Gnd Sizo of Hose. bene I Comdle is moved closes te the mirror, How woud Hu screen hove to be moved ? Sol, Sixe of candle (0) = »Sem. 3 Ua-27Em, ——s R--36em , f : RJe = ~18Cm. ito, 2 = A 6 \ -i-b S IV OS = voy Uu tetat 2. -kb vs - S4U tm. Vo -18 27 "sy = So the Stveern Shows be Placa at su om. trom the mirrmoy om the same siole as the object. th LT dy size of image hen or, He imoge. ds veol _ --2b 2 “Mise Menge oy iu ~£ os (su) = 2a . a a ep) 2 I sem Minus, oi Incicates that im & ws‘ ivertest. ri os. ee When the Candle us oved clisen fo mirror, the screen how odo: be moved away teem the minor. Howeve édohen Candle vis at a “distance Less than 13 cm the river , image. pemecl would be virtual amol sckeen us “not wequived as the virtuol image can nol be taken om the Scrten. S Use +he mirror equetioOn so Show that — 22" (a> An ekject placed between f and 2f of a Condave. mirror products a real image beyona 2. (6b) A Convex mixer al woys brooluus a virtual image inclepen olent oy the bLocodion of He object. me (c) Am |okject placad betwean the pole. and focus of x Comenwe mivvor produus a virtual + erdangec image. *K Retrachve Imdex' ws a characterise property. of theY meclium 5 whose -velue oclepencls upern, nature Of material of the meclium and the Color or Wavelengity ob highs . Laws of Refraction - Ud Whenever. Light es ome, orunal dua sty: Gant hor, the frequen oO ( omnol phase of Xi o not chenbe: ane ob RE ieee ob Rgds we hee wenetengihy ob Age charge: Gi) The Inerdent vou, the ve acteo ie and normal to the Interface at! the Point! of inet co, abl Lie mM thre Same plane. Gi) The product of; mafpatltve inox amd sine of angle of incidence / vefraciom ot Q@ point in a medium is) comatant. 5 Sins AbSinie LH ips e ond lr = Vs then MM, Sink = AQnsin®r ov Me . Sint = tu BU) Sin ¥ _= toherne $M, OS refrachve nnclex of medium 2 ‘with to medium 2. | inal *K Thig Law vs also catltel Snell's Law. For the Same valur ok ane of inclolen ces the angle of refrctio in Doe he Ai& and © are Bone is, us* and ase respect) » In which |meclium woul the. velodty: of Lu be wWinimum ? Sel Fem ‘snell's Lac - AL = Sint = Sint Vv > vasiny for Given L Hence velocity of a ad minimum m meolium A a> ompe of vefraction is minimum Cis ae treough Q rectangwwor Glass Slab in. figure ABCD Ud a rectongilar glass Slab. cay iat Mis baataiaact clon the Baw. AB bbfat Lt). Jd reaches al The retractest Lm falls on face cD of Lio ana nas along | min ot LY. AIR (Mad In; gen fom OO Yaver mecium 40 a denser the Bends towards the normal ond in clenser to & vorer. meclium, te rey Gets Buty ou feo the. norma. plying snell's Law of Le eae Ae sin Ly = Hg Sin yy sin Ly = 4s _ au sin vy Ma ¢ © Again applying snell's Law at m - Ag Sinig = Ue Sint, © 7a 2 Se = 4u, | -—@ * Accoroling do we ie ek of reversibility eff Light who fined pot of b bight ght any number. of vefleciiors oma repedctions dan the vou retrace its entre Path- % LoateroJ Wwe Know that “Me = Fn Hence prom eg. D and (QD we get- Sin iti = Sin vr Sim vy Sin ta ® Fooum figure - in = ¥, Se Sinisa = Simr) Hence prom. 29 - Sin m2 = Simti or Xa, = by * Hen the emagence roy MN as parallf ao the. mncidant ray KL. l Expression fov Leteral clisplacement — fro Mdm min! Perpenciicilas to KL produud Se the Leceral duplacement of the wey on passin Treva the pea! Sleto a? nt 3 bat ZNLN' = & = clemtecicny o1 fivat veproction - 1 sims = MN um | 2a MN! = LmMsin& ; — @) ‘ t In a iM CoA YS Loe LM OM es el =-_t Coat) Cok Sy} | where tz cu 2 thickness of qos alok a Se Frm <4 © ne Get — mn! os ow Sim, Cos x, mnt = tsim Cli- 1) acs kee eens CoAY, TAra is the expression for Lateral clisplaamatt, isplacement in pwoparHomot sto Hee Hhickness (4) eh the Slob and angle. of inciderce Ly. Essential Conditions for total Internal Reflechon — GQ) Lb Showld travel pom a denser medium so Qa an mecium. ° Cid Ande of iInciclence. Im clenser meclium shoulel be greater. than the. exitical omgle for the pair of mecia mM Contact. Critical Angle -~ (Cc) - The. omee of inciclence 1m Hae ‘clevisen_meel iin Corresponcling ao which angle. af refraction Can the TOR mecliurs is S30 5 Gs Called esitced omale. for the pour of medium M cortact. - It ~ represertes| b be! and Ute volun clepends on the nomurrc of me Lue im Comtech. Relation between Re-fractive index & Critical Angle whon L= Cc > rs 30 Applying Snellis Law at Az, Hesinc = Aa Sm So Ab = d Ma sinc Q = Tore au, = b = smc . bc olerse t As A cepends on wavelemgth , thurefre cntcal amade the Some Ppalr ef medium in Contact will be lt hes once for clifferent Colo*s- Applications of Totel Internal Reflection | (1) ‘he brilliance o¢ cliamond - The. bailliong of cliamoned 4s due to total intemedt redlection ok Light’ Ju for cliamond Js 22, Se thed cxiticod omete +x Uemone ane interdace os calcutot ect for a . : : My = dfsinc we 2u-u" critical angle Ce) - en the chamona ma at a@m an game trie 2yey, Tne a Y,, Fe fe muh ple to inteanal yetechos ah ws panies acwds~ and remain within the cliamond ome does not Come out. Hence the diamond sparkles The cdiamone Uy cut Surtably so theg ae (2) Mirage - Miroge is om obAiced illusion cohich OCCURS LAL ivy clesert On hot summer, a TRe_ olyects Such ah a tres CUppearr +o be Jrw. 4 As iy Hee. tree is on the bank of 4 pod af water. on a het summer, olay » shemperotire of aly nL the surface ob eandy GA maximum. The Kp per Loupers °b Ouv nave arauadly of 2crendin phothedane There: lens, sepacHve imolex of “A om incre ing slid | with hetodct above 1,4", att oF of a tree ‘successively “nob. BT beP rst be bending eA, G. pe 4 normal inciclence ARO At la aheicudi, layer, wher om@le. fh n ban of Beal an bn becomes eaten, +ha Wee occurs ana tee ia rh ref lected no bbls ato imbeanet chu r orcas he ObseAVver along Come fom Dy the mirror image TAU avert-ec| lamneg e of el og > Creates the. Imprexdsion ok reflection pon a pond of wottr. C3) Tetally reflecting glass pAisms - TRise Ghee x19 omgled Prisms vwohidh turan the Aas thous Co or }80'. are baseol on the phenomencr7 of totot infernef reflection of Age v Hors UA 15 So that critical angle for To totally reflecting AAS = an i dt ce A UD” ve me AAS AISMS e of imc TCR LAS WH 4s Lote wad Pramse than the cxrtHcel Tog de. ok the. en fate. Hence the Aight Doucffens total AAS - atx } internet refle Ctimm. : Qa Pi cafe mite 45° 45° Bere p B —— me 45° FOE 45° (4) Optical Fibers - kena col fibers comalat of Several thousand, ne beas o lass O of ey tong 0 ead feet ° Jt oll. OP Ie cm wth refractive den ok material of the ovdley “of 15 Civ) Principal axis .- TR ine Parse through the pole and the centre of curvature ob Spherical ere cting Surface , extenclec| on eithur sick ~s Calltol “Paindi pel exis. New Catute sian Sign Conventions - 41) ALL Ustanus, ore measurecl darm the pole Of the Spherical vekrachrs SurFack @) The clatanicts wreasurarzd IM the. olivecHtm of imclolence of eer ane taken ob positive ome} the Sirtonea? po a OlirecHom opposite to the civection of; rama ob Mgt one, Paen “A negots ve. Assumptions - (1) The object comaists ok a Jaying the paincipal ans 8b the ephenient ie Hag Surface ° CH) Tre CaaS UAE of; sphed cal refracting su face 4 Sm Git) The. Mnciclent ame! refractec| make sal angles with the pAlncjped axis oft the suAdace: So that -. Sint x L | anc | siny ¥ Refraction from Rarey to Densev Meclium at a convex. spheucal Refracting Surface - Ci) When the rmese is Real - Let Q spherico) refracting SUeface XY separate a warer medium o refractive inoex Mi fom Q olenser meollum of Yefrachve incdex MM. PSuppose the Sunface Ws" Conver towards rarer meclium Sidc. Let P be the poled, C be the centre of Curvajure. ad Re PC be the raolius of Cirvaturd - o DENSER-1, e Y 5 A yoy of Li startin fro 0 amo) Ineicleut normally on He cDajale xy along OP parses Atrophy, Prothea roy of Lied fnciolent om xy along oA at Li Zs rvefractécl Glon At at “Ly; bendlin towards the normal CAN. The two refracted ways actually meet of Tl, which us the reo rmage. of oO. From A; drawn AM perpencliculas to OL. bet LAM rr ; LAIM = B ame} LaAcm v ou AS external angle. of a tbrangle ud equal do sum of internal opposite. es, therefore in ALAC YT +B ov tT Stmilasdy in Aoac i= way } —O n x 1 w According do snell’s Law - Mi sint = Moasinr yi 2 Uap [angles ane. Arnall | Using - 9, GQ we ath - MM, CAF) = A Cr- 2) “= Pagies X > and wr are sarall so Laing p= tang aa (BB BE) 5 ug (at =a PAC MI AS aperture of The Spheuced Surface is Small, mi is Close tU P. Thercfove - MO 4 po > MIS PL Mc PC | So wt a | ! My (ea +See) = Ma (ze ~ pr) ‘ Ai 4 Me = A2-H; Po - PT a | Using neind Cartesian Shan Conve nHons& wre Geb Poz-Uu > PI = tv 4 PCER Ay 4a Ae My My -u v R : TAta 435 the requirest relokion veaming refractor) fom yorte to csernser meslium QA Convex SPhericcd refrac cH ng 1 Surdearce «  Tn Acac § LaY¥-a and in Atac re7¥-B Pathing these volluer of b.omel 1 im the redatton — Ayt = Jar ov Ay (YA) = Me CY-B) As angles ake Amal, using: ex tone» we ef — AM AM _ AM" AM lime Mo = Ay “™Me ° ML = - L L or ile we] = Ae [Re oe AS mM. db Chose * P because, of Amabl aperture - UY ~ = Lo OL Tends) = DRA a5 or -~ 44 = Ade - My PL PO Pa Using Naw cortesian Sign Comentiong — | Po = -wU 5 PIT co -v > Pes-R Me ~— Mi = M2 My -Vv -U =R or —-4Ay 4+ Me 2 Me dM y ua Vv R T+ be the dusiret rvelodion. | | | Refraction From Denser +o Raver Meolium Ch> AT & Convex Sphnrical Surface - Let P be the Pole omel c be thre Conte Of Cunvetute of a spherical refracting sunfact xy. This burfoce w2 Convex tywards the rau meclium and Separotes a clersex mecium of refractive Wreltx Ma. from Qa yarey medium of refrachve Index Ly - Clearly Me > Hh, - t : ih a ' Ome naar C MIP i j 4#—R — : U , 5 vw a : : " DENSER-p2,/ | RARERH, Y Let O.be a pot abject ing on the principal Qxts of the g herica) surface. A voy eel f git OA Oe < Oo meets the re etn eunfe ace Lo On refackey Te bends Awouy yee Dea Mbned E CAN omel moves eulong. ims aL Brother. coy “becom OP falling noyrmally on the refracting susprde undenviates| PL. The tuo refracted wos AT omd PL actually reget ot Ty inhich A therefore the reo} Lmag e. ck the. Poimt obec 0. Ie bo amd x ane the omgtes of imciclence anol refraction, Phen from Srellis law, we hav - OY MeSint = AnSiny As tomd y we small So Smiatl amd sinre So Mz = MM, " | In AOAC, ct ¥n In A TAC, yuytP | | OY MaSint = A)Siny As | cmd ane Amall So Simtivl amd Smray So |; Ab = Ae In Done, C2 Ya In A TAC, rzrytP So that Me C¥ =A) = any (e+e) Foam A cow 4m perpendicular to of - As onggtesa he. ameall , Se Hsing 9=tane »we get - Aa [Oe = Att =, [am 4AM.” ‘ Meo Mo MC MI a . Put. A - i Me Me ao_| ee ad [te + Slee. eature of the refracting Surface as 4mall ry 4A dee -bo py ob i d f i we MOR PC > MO RPO andl MIM PL a+ te — 1 = aL es Ma. | men 3 | . a foe + Ss | Applying. TRI Costesion Sign Conventions - PO = —U >PIT=v > Peis -R Ao + Ad = Ae Ady =u Vv =R — Az + Me = Ae Ho ui Vv R Ts is the relation seman refraction frm clerver to yarer mecium at & convex spherical refrachng. Surface. Important terms relotecl to Lenses - CG) Principal axis — Tt wa olefinec| as A Sheu Une povssm trough the cevtred “of Curvotinre STS sunhaais ¢ aq tens. (2) Optical - Cent re - atten! oe ct Beker as om point tefl om the PAncipel axis Se that @ ¥ of L passing Hn at cloes not Suffer an satatey fom its Je ot gous Uneleviatecl 5 uc? Hout omy. | Loterot | clidblacement. «3) Principal Focus - , | : when a beam of Labt 4s meident om a do lens 1 a olixectom Hee princi ped AS of the Lens , the tee vefrarchorn theo the Len& Converge to Cir dt of Re Ler) vr opbeny to li verge (Sin Case of Concave Lens) a pein om the “principal axis’ This point F js Known as the prnc po focus of the Lens. CF =f uw Prin po focal Length of tind Luna. optical axis optical exis paratlet rays of light parallel rays of light opticalcentre _prindipal axis we _f — focal length (CF) focal length (CF) (4) Aperture - . Aperture of a lens is the effective chameter of uts Light tromaritting, area. : Lens Maker's Formula - Tt Ww a relation that chines foced Length of a Lens to radius of Curvature ‘Of the two SUBfates ef tye lent ome refractive Index ‘of the materted OF the Leys. . . UThe Lens makerls saarinatals,* us Usetul in ° olesig ming Lengsed Ck eal veo) focal using suitable cotead al ond surnfacts of euttokle Yaclius of Curvedture. New Cartesian sign Conventions - Gi) AN clistomensa one measwucl from the optical Centre of the lens: Ghd AL he cistances measuroal in the Urection of Incidence. off Light ang Fakon ov» posi tive 5 coheveas all the cdistanws measuricl in a direction opposite to the clivechon of incidence of Mags ane taken as magenta Gli Fer @ ‘Convex Lena, F ts positive ond for a concave! lena, f U negative - Assumption s 7 Ci) The Lena is Hain So that clstances measurzel pom File “sealed of ts surfaces can be taken as equal tts fom the optical centre. of the Lema. Ci The ob Consists o Q point Lyin enn era. parind pal axis of od ob r ang Gi) TRe aperture of the dens, ss smalt. | (iY) The ipatelav a refra make small congles, | | with fe doiedpa oa. OKs ob tn ae | Beviveahon of Lens Maker's Formula fov Convex: Lens - . | — Convex len& Gs mack up of tin convex al daw ‘Mifeation Tha gined: rmage. pe apie ture In figure: Py), Po wre the poled, Ci Co Are the centre, e uravature of tue Surfaces of Qa Hin Convex Lens RY “earth eprical Centre. oat c. : heat Jtyp be the ve fractive index of the matertol of the lens and A be the refrocdive index of, the Tarver medium around the Lenk, Comsicter. a poet L ere ara ans of the lens. A fi ming from oO omd iniciolunt normally ery the Shades aR mg OP, Passes Atraight. Amore yoy Inmcichent om XPY wong oA 48 refracted along A® T+ the lens materlod weve Contmuc amd there wear m0 hecond Surface xXPY of the a the refracted w AG usoutel ge Straight meetin ng the savst refeactes) wo (ot TE, . Thenefore “ZL, wot Aave. been Q rec erage ‘of: © formed after refraction ot XPRY. As the refraction occuss yarer +o clerser meolium Sa We Cary, Write - AAI M2 = Ada - =a7. * Vi R @ (ohm CleAl = vi, cs P= Rk) > CompRor-t) So - Alal = eal — @ But Cp = AB _ AG cr From e9. © amd @) we ge ¢a! = Fa! = C&- cr ce cr CF Using Rew Cartesian Sign Conve nium _ let “eps -u , cae Sav, 5 cra tf MM = v-$ U FS veo =s -uv +uf on Uvioi= Ut — vf Pivide both sicles by uvf ,we gut Ae idk f Vv u This Ja the Cons formula. Gi) Virtual Image - lohan the object AB Ws held Elose An the. Lens, between Comd fF, the Imeoge A'@ formes by Cenverx lens is virtual , erect amd magnifiecl . ' Dee Note ~ ~ As AAelc ond A ABC ane Aimilas , 30 ethat- Ais! _ cel ' AB cS : e Agein os A ala!F ond cpr are similar (ee thot. ' ale! 2. oak ecb Cr But ep= AB So- Ala! . BF —~ & AB CF from eg. ¢ >) we att - cea! = oe - ¢(~@+4e¢F — ce ‘GF : CF Using new sign Conven Hos , wre Put — CBR = -u ce = -Vv CF = +$ 4 cae > a “Mo si ays —u 4 £ enein both Sioa by uvf j,we get — or uv = uf - v¢ K Leng ceed ts the Same vohethe Image is real oy. virtual. A Convex duns oh ve frackve index Ls has a cose fora Ah ob iB nah tm, Mm alsa + Cateutate. the change 5.008 oe ots ee when Ct is immexsecl in water. of Zee” Innclex 4/a. Sel. Gave thet - AM a Is = 4/3 F, = 18cm. No w = 4Mg oc tS = 45 w Mg aL. 4/5 z AS a clue Ao-b if (a4 Ly Ry x) , $2 = (*a3 -1) - (s-1) : F, (Waly 74) (42 -1) | fa = | Fy * = Sa = 44s fa = 4x18 = J2em. Chemge in focal hungth = 72-18 = en | (Bd Contave Lens - [In this Core, the im al virtued , objec . 2. formeol ws whotever. be the ponies of the heat C be the. optical ners ond F be te principal focus of a Concave Lena off focal lengthy £. AB hes an object hele peapencticutons. to the principal axis of the | lena. oa Virtuel , erect amd smotler oak Aisi Gs formed clue to refraction Herouwgyh Concave. lens. As DB Alte andaAwe are Similan oso thet la! AB -. cB _ () AB cB : agen aos A ABE amd A car ake Similar - - As . BF “ED CE 1 But cD= AB , So Heat ae! - OF _ @ AB CF. from equation (1) emo @ I CB. pe = cr - co! CB Cr CR Using New Casdeniony Sign Comnvetlterl 1 wre. get - eSB=-U 5, CB=za-v 5 cr = -f e Try a Concave lena, pmage doemed A duos | Virtual, as shown in figure. So aia! . ea! AB cB ih =f = oO =u or _ _ Vv MSS 7 KHence the Lintar mi ni fication jn Case of & Concave Lema i A worgs postive, Power of a Lens - (CP) The obi Lity of the lens to coverge & beam of Ada foiling oN the hima Ga Coctleol power. ols Lens, Tt as measuresl at the reciprocod of focal leneth o the tions. r ¥ 5 pe & Accercling to lens meker!s formula - | ee o = Hole E) For Q Conver ain Len’ 5 power SA posi tive ana +r a Ai verging Lens 5 Power. sa negotive « or HB The St unit of power us Clioptre. CD): l clioptre ~ ome meter. Let AS the power. of a len, of foco Length * when f is.imn em: P = = ise @ Find the radius ay fainaractne of Convex Surface cose Of & plano Convex lehs, whose focol length is o-3m Sol. Rj = ere omed AA = Ls, > Rat ? o> feo am, Hels -i <= 4 = {00° Re SEX OS 1S. Rg = — 1s ™. A Conver Lens macle up op Gers of ve fracchye index ot bs ds clipped in turn, in (4) a meclium of vepractive Inolex 16s (2) a@ meclium of refractive index 1.33 | will ut, behave asa Converging ora cliverging Aina in the duo Coser ? Seals Frorn Lens maker's formula - - = ("lg 1) (%, - &) It Lod wg GE) As Wg, < Alm ¢ for the first maeclium of refractive index £65. Ana Fg & Ady, fer the Aecone meolium of refrach ve. inelex 1.32. Hence, tre value of focal Lurgth f will be ive. ‘ +| ' ln the frst medium , SO the convex fons behaver as the — diver ing dems for the first medium . The velue of focal length f will be positive In the secend mecliium, se tHe Conver furs behaves a& he converging Aang for Second meclium. ia) A beam oh Hert Converge’ of a pont Pp. A ces® Cave hens of focal tens leem. ig placecl 72" in the path ef Thha bea 12 cm. | pram f Drow a yay dfagvam and find the” locotion of the. por ot Ywhich the beam would now Co’ VOAGE » Sol. | | u bela cm V of taacm, £ = -~ (6m. ‘ _ 4 Using lang fosmula - ;2 4% ” tidy 2 Lm > Ae deb 1é vo oTh > 7 > fe trod > V=tr4sen. Tr hmage of virtual objeck at .P forms ad pl which dS at a” astance +2 em from tre tens. ‘ \ A screan dd placed » Joocm. from an object. TRe coe, image of the object on the Screen 18 formed by 2" a Convex Lenk two a docations , separate by aoem. Clcutate the focod Length of the Jeng used Sel: leu! vy Scveer abyeck end screen are 100 em. from each other. © ' Dur 4d seventible Imege of Lagi V-Us 20 em, “+ Voo= loo Cm. @) Combination of Lenses in contact - Im |variouws optical Instruments , ‘tur or nore. Leysers Cembines! +p : Gi) Increase the mogul fication of the imoge. Gi make the final image erect wert. the object. ~ Gi) yecluce, certain cbervatons (ie olefects oF images by single lens ) , obtain the position, abt, Oma nNoture of Te the fined Imoage produces bby a Combination of Lenses, we fivet find the imoge of the obj ect formed by the “first Jins. . “TWA i page acts as aM object for the second lens omel we lo tts imege. Te imose formed b tre setonad lens serves AA “the akjeer ev the thir lens oma So ov. Focal length of Equivalent Lens - (a> Both Lenses are Convex - Lot Cy; C2 be the opteod Centres of two thin Cenvex Lenses Lis omd ba hele Co-axially in Contact with each other in ain. Suppose fi, oma fy ae Heir respective fecal length, ta Le Let a point object Oo be placeal on the Commer Principal axis at a stance OC; =U. The Lens Ly alee oxoule dorm its image at I! ehere ct! = vi. Fenn the tens fowmula - : ao bee = oes + © zt! would serve. ah a virtd ebect for lens La, vohich forms O° fined image TL at “clutente CaLav- As the Lenses ar thin, therefore for the lens ba Uz Cot & at = vy! from tne. Lena forrnuta for La - bot 2 4 VME — Adoling | @D oma GZ, we get- Loo Jl = ok a = vO u Ff, ~ fx cS bet the tid lenses be replaceol by a single Lens o focal Aangty F, which forms imager at ‘elistance v of OM objec. at cistance U fron the lens. this © Long - took ce Jb ses (y Vv ua FE F FE 7 | K+tge | (b) One lens is convex and the other is concave , Ty f, Ys the focod Length of convex Lens amd fz ds focat Length of Concave Lens, Hye their equivalent foced length F woud be Given " hk La FO FCA OOK Foe $ife lll os, . | There aha three Cases anise - Core Li / ———o It dro= fa ,then Fae. The. Combmotion wodd behav Like a plane qioxs plate . Come 2: | x4 f, 7 fa then Fo, ative . Therefore Cembinodion behave as & Comecave! lend, Who Gochl iengin of Convex lens 78 Langer— Cone 3: ; TH f <f2 Thon F AS positive. Therefore Hie Ccombmoaton wore behave asa Convex Land » op focal length of Convex lensis smollir + Note- | Ci) Th the lenses of focal lengths d fy heal oe ede Rime Te, Plead login F of! te ecuivolent lense is given by ~ Lt = i ab _ ol ee i). Tote) Power. of any number. of Lenses in Contact As tol to tha algebraic Sum of the Powers of maoliwche! danse. Piz Py, + Py teen Pr * I the Sim of the tuuns om right Side Is posi tne » the System of lenses woulel behaves Like Convex. * Th the Sum of the dams om right side is negodie, the system of lenses wollel behave as Concave.  ANGLE OF DEVIATION (3) 8 c sma ANGLE OF INCIDENCE (/) | Tn the minimum cuviation Position, tpel,eb AS C = ly, » therefore T= Yn xcY Then from ushion @, 7 | YrreA 2, ar a Pom |. @, Sm = ltl-A ov A+ 8m >= 2t or i = Aten Ty oa refractive index of the prism (rd. air Thon by Snell's Law, , ‘ A = Sint . = 5 Sin (Aas) vere Sin Aj TA reletion a. calkcl Prise formula - K Tt Ja weol ter accunsce detouminodtion of; res fractve inelex of @ Pronspartni mecuum °b which ie prism ib made- Dispersion of Light - TE 48 the phenomencn of splitting ob a beam ot white Light indo ots Constituent colours om parsing thaugrn a prism: The bomd ok seven Colours So oblained " is called the (visible Spectrum: at Thee orc of Colours +e lower end ok the spectrum 4s violeb (V), Inoliga (2), Blue(a), Green (a) Yellow CY), Orange (o> enc Reo CR) ane! Can .be qiven. by the .word VIBGYOR- WAVELENGTH (A} sessed Cause of Dispersion - Each Colbur has ts orn wavelen CAD. According to the Cauchy's formula , refractive ‘Liclex (MY ef A matertoel Axpends on wavelentty LA) of errt as Ae Axe Bo + So 4... (one A\B,C-- a OM Ore Cmatends, M of rateual of prism is clifferent for obifferent Colours / Wow ‘ As sieht of ctewiotion Ls Se (A-LJA As Mot Prism is clifferrrd pr oU fferent Colours, therefore cLifferent Colours deviate Hhyrough Aifferent angles porsing. thrown Hare prism. Thia 4s the couse fy olinpersion- As A violet < Aved Thonefore MM violet > Mreal Hence Svieek > Sred | be maximum oluviation for violek Colour ark minimum aviation is for red Calour. | Angular Dispersion - Angles Aidpersion produces by a paism for white Js the cUfjercnce im Hae ome. oh cheniotion of 4wo “eme colours Le: violet and reel Colown- Angular disbersim == Sv - & AS Svs (lv-1A ond Seo (An -1)A Hence Sy- Se = (v-I)A — (Ma-NA ox By - Sa = (v- AR)A Dispersive Power Cen) - Tt . dufinec| as He votio of a low oLisper— Sion 4d +he meon clewviation prooluce be He prism. Tt as represented by 0. Angular cliapersionr meomn cleviatiorn | Atspersive Power = By geometry, angle of maickence (L) ef Al tee fours is 4se ot face ac. Liqdt suffer dotel interned reflection for tolich His omele of incidence 28 greader thom critical ange. A ° Dv L > le : ° , ? 4s an D> Sint) > Sinte B ‘ . Sin 45° > Sin le i 2 s. : ” se . Se ——r A Sin 4s Sinle Nien gz B c Hence 2 < yw a ‘6 Total internal reflechon taki Ploce on ac for rays > Je 24-414. Hence reen amd blue. Suffer tote) Internal reflection whtrecs ved Undergo’ refraction, ome reol colowe vou will emeage out of face ac. @ S coctering of Light : . When sunbent Fravels Hough Hae, admosphorr, a4 gus Scottered by. Ae 2 number ok rdlecudes pAbent in the atmosphos, His change in clirection / of the Lig JA Callecl Scodtering « According go the Rayleigh , vo size. of Scattiver Ls edn “armettie Te degen of Be 3 Then inches ty of; Scattered Light CT.) is herds proportional to the fowth power of Haw wavelength of ie clent Light CA) . ‘’ x | KOR Lag Scochrexing Js voliol ory volhan Size of Ss erer Lb much smealur thon wavelondt of, Lgict But When Size o Scotterer 14 ‘much green than wavelen: of Le then hud sceactheune JA no Gil, Oa sevelorgd De scotksed Applications ef Scattering of Light - (1) Blue Colour of Sky" Liga arom the sun When, while travellin a through “earths odmosphers , acts scottersol by bonne number of molecubers In the earth's atmos pherac~ For Upper A exs of odmosphere ax Sh A, hence Rouyluoh SC ung iy valid. The. intensity of Scattered ye) varucs Inversely 94 the fourth power of woavelergtty of Liaht- A blac colow. has a shorter duaveltn An than Yeol ; fore blue Colour is scottersel much more and sty Looks blue» OW C2) White Colour of Cloucls- Tre Clouds care at much Lower height. Tre Lower. peod= of admasphire Conteuns lorge. clust particles y wotr choplits, ice perticles etc. Tn this 4 COAL Size of Scotter Xr A, Therefore all Wwaveleneths + are Scetternocl nearly equolly « All Colours, scotteud “A equally rue to give Us the Serisaton of white: Hen Clouds jenurolly appears vohite. (3) The sun looks redelish at the time of sun rise and Sun Set - At the time Sun wise and sun set) the sux is Aeoue tae horizon. The ¥ the Sun have do tree) a dange pert “he Daphne. AS Ap 2& AY and in enarty of scottersdl Lignt Ts 4 Uy -, therappre mo&t of the blue Le Ads” Scocktexicd) quay. 0 veal colour which is lest Scottterscl | enters our eyes Ard abbeans ty Come mm the sun-|Hence. Sun Looks fetd both tre time of Sun Se ancl sun set. SUN NEARLY \ OVERHEAD ; LESS BLUE BLUE.SCATTERED SCATTERED “yer :SUN-REDOISH 2 a (4) Demger Signals ane red - As moryelandHy ob xed Colom. is bi 2. and Is ~ Yat 5 theadore. . red Colow. ts teas Scoctteres] and can be Seon trom dorge. cistance > Retina - The Imege of an externol object is formed y Hae crystolling dons en the TeHra. Tae retina is a film of nerve fibers covermg the cuwed bock surface of the eye Jo The retina Contains rods and Cones, wohich serue Li intensity anol Colour respectively. Peanamrt electrical ee al via the optic nerve fo the onda, which “ finely process His informecion: Aqirows humour enol Vitreous humour - mk eye lent cleviolis Hag: interior of Hae cyte iwt> two] Chambers The anterior Chamber between Cornga and tr. Lens Comtains a Wot ery fudiol Called AGUEOUS humour 5 and the postertoy Chamber betwean dans ond t yetina contouns & trems parent jelly Called \vichous humour | Importer Peints - I Gi) The Shape be the curvature and the focal Len of the crystodling hens Con be moolifiesl by the Gliary muscles. The average Yefractive. index AU of crystalline dems 4d 14% and average ve frachve. inclex of agueous humnouk and vitreous humour 44 1:336- Gid The temat sensitive. polvt on the retina is Called the blinel spot. There ds another. spot ad about the Centre of the retma, whith An most sensitive ao Lads This is. Callsol yellows spot. (ii) The ability of the eye 4o chseave clistinctly the objects situoceel’ ‘ot willy clifferent clistence prom the exe 4s Colles) accommoclection of the exe TH becemes possible by changing the Cwatt of Lena and hence sts focal Lngth “by a change In tension im the Ciliony muscles holding. Hye Lens. CIV) TRe most oliatant peint whith an eye Can olaserve Cleasely BA colliol Fax Point CFD Oh Hat ee. xy GQ normal eye F dies at infinity: (YI Th the object 4s too Close do tHe eye, He ; luvs cannot Cume enoual ‘do focus Hrs tmage .a om the yetina. Therefore Haw image us blurred. The cCloseat clistance for. which Jens Can fous Light on the retina is Colle the Lest olistine of olistinet distin, of, the olistance of Near point (N) of the ea. for a nownal eye y the east olistence of elistinet vision i d=z2se¢m. a Defects of Vision- Some Ceommen opsAical oukect of the aye AL: (1) Myopia or Shoat sigitedness (2) Hypermestropia or Lang si (3) Presbyopia (4) Astigmodism (1) Myopia ov Shord Sightedness - Myopia er short Sighteolness iS Hot defect ef human eye by which he eye Con see Heavy Haz. objects dying neon Lt, bud the: for off objects Cannot be seen cbutinctly: oo Hence fer. a myopic. eye. Han for pomt Shift towards the ey@, Tt Gs no longer ot infinity: T+ a of F Normal Eye R (Sharp image of ° object at infinity) | The pic , aue focusses the porxolli r age OF P i front of The retina: beet, ne miopic eye focusses re om a peimt Foon the reting Thus F ig the for point of the myo pic eye. Tt comnot See Cl b mo =F. ‘ an “ae | . The tuso pessible Caused of this Ate ct ArLZ! (i) Tnerease in site of ee. beth, t-e- distence ok setina from the eve bons increases. Gi) Decrease. in focod. Jon ok the eve Lens, Ldhin Hye eye. dd fully Slane b “g Correction - To Correct a m pic eye. ‘the person how to uke Spectacles with &@ Contave Lins of suitable focal dan . Hence the posaltel r of from infinity oft. vefrackon through fne. Lemenve ue Cer to Come, fom F.C the for pot of the miopic eye) - ae a R Corrected >>> myopic eye (Sharp image of object at infinity) © Let 22 be the. distance of; fore pomt of He mippic exe. ond f ibe the focal Langtn of doncove. Luna” to bee usec. Now fov Contave link Ur O 5, Yo -e A 2-eitew ke a - F Vv u oY 2 f f ce -mt or Hence focal Length of Concave tens put in front ot the eye’ shout be eguol +0 istonce of far point oh the cepective Cmiopic) eye. ie ol ont of a miobic person, is 20 Om. in TAL Pp pal BS from | of the cee: bihat 1b the power of the Aus Gs to enable. him 4s see clistant c 2 Im whet wo clerk the Convective hs hyip tha, abeve person 7 Does the Lend magni very clatont objects ? Explain. 1. st Bo x1 P =-l.1s D The Corrective concave Lens clivesges the Paral] ous from olistant object ars 44 Trey ane Coming, fel Yan point F o 1 Atp& aloes not magni fy the chatant objects. Sim ple Microscope. or Magnifying Glass - A simple: microscope Consist ok Converging dns obs smell foco} Len . A virtuol, exect emnd magnified image of the object is formed! at the Least Aistance of Aistind vision from the eye hotel chose to the fend. Mot 44 tah the simple microseepe HA -y alko collecl a magnifying Ghost. 7 d———_—! AS ee: i a Ay Reet | | | % | | | , ropa Bi OF BBS \c F i | : e— u —>i * Let an object Am cs held betwean optical centre C and pain cip ol focus F of; He. Lend Ppenpen Auton do tre prameapal axis. A virtual | erect and megni Heal image Ales Ja formed or traceol in Fig: The eye it held “close to the Lens, and casa (= 25 em). Magnifying power of a Simple micwscope +48 a clefmeo| 4s” defined ab the rato of the angles sublende - b the imoge and the object om Hae , When bell * ake abthe “least clistmer of clistinct vison from exe let LaA'cB=B and LAyc@ ex, By lifinition, Magnifying Pocwen (m) = Be for small angles Lane “we | Hence tan oo = & amo imp = | _ ton Pp Mm tan  In AABL tomp = AS ce Tra A Ale «tema = As =. ae cp! ea Hence m= AB, ce . cal .-v's¥ ce AB tea. 74 u - a ee i i - Voo21-¥ Multiply , Sioltt by Vv ¥ = i-¥ ¥ Vos ie = 1-M oO f ov YY) T a : a but Vv oo ol oe Mea (4 + o) TRA Han expression for magni fying — ok a Simple rhievoscepe Cmaanifzing. aos) K As fF lolereoses , m increased Le. Smatten the fotal Lanath of the Lund , greater Ad its moranitying Power > | |. Now We Know that -' Me = (1 + a) | Where Gd ds CB" = feast cuatence of distinch vision ond ££ ib the foc Aungth op eye Lens. 2 Al B = ae! = ve Also om, =, 28 a i Hence. Magnifying power, mis Ye (1+ ob leng+n ef microseepe tube Loz. Ve + Ue | e 1 If the object AB fies very Close Av Fe Ue = oe ROR = f As Ala is formed! very close doveye Lens, therefwe Vo = Ge xce, 2 be length sk microscope tube Hence. ne gat im = (ita) = i (4+) Note - (1) As maganityin power (m) ative , the tmage. , Sean ra St ee ad wife invessteat, Y GQ!) Fer forge maging power-- f. and f, both have. be Smoll. Also f, id adoken do the ars Hac de So thot field. of view mou be. Imerens’ RIA compound micedsco pe Used an obyective Lens cov OF. focal Aungth 4 em, and eyepiece Lins of- foc Aaungth loem: Ay object “is placed ot ¢ om. the objective. dans. Codcutote the Y ing . power of the Compound microscope . Also Calcawete Hae Aangth of the micascope - Sol; Given that - fy = Uem. fe 2 lOtm 5 Uy = -Gtm, Mes D = oascm. For objective Lena - 221 -h0 qo Ve Ue = a oo yo! oo , > 7 We + = > Vo = l2 cm ; i ‘sc te Vo 2. Meern fging Power tn) 2 (+ z | m= -IR agyo. eC SE): -7 Length ob MICrD Scope. “se |Nal +luel for eye fork > Ve =-28 em, fe = lDCm. by Lena formula tod ok fe 7 Ve Ue tos b - d a ne Ue Oe ? te ~ =re ~ 16 = Ue = -So 2-7 ly om. t 7 . 7 5 “ Length of MiICYOScope. = [2 + BY Le= {9-Juem | Astronomical Telescope - | An astronomical telescope ud che optical Instrument cohich 4s used fox obsexving cliatimet images of heavenly boclies Like. stons, plmets etc. , * Tt consist off two Lense’ 5 the objective lens which 2A of lange focod dongth and lange aperture a and the tye Lets, which has ao small focod Lengtin and small aperture i Tre. two densedXS AKL mounted Co- axiabby at tre free ends of the two tubes. The clistance between +here JonseA Can be. adjusted using. a rack ane pinion. anrangemend (i) Normal Adjustment - Leb a Posrobtel beam of A from an a&tronom'! cal ablect Cot mfimty) is made do fall - om the objective. duns eh the Aelescope T+ forms a veal, Mverted and cAminished image. ala of the abject. The. eye ‘piece Aa So acljustecl thed Aa Lies juat oat Wy cus Oly He eye eco. Therefore. a fin ot igehay magni fice! image iw mec) ot infinity The. final image 1s erect wit. Ala and Js imverte weve te thee object - OBJECTIVE LENS PARA FROM pe Rays 8 EYE LENS INFINITY ECT. AT In A Awe. 5 tone = A& e218 nt a! , } In A ABS , tong <= AS eB | ! _ = thot - | m: Aal x OB > a = Fo Qs AB Ga! “Ue Wohere fr L focad engin ob objective fens andl Ue = aidtance ok Ag » aching. OA the object fox eye. Lon. 1. Fox <Y suns i - = = + f = = 2. or -t te” 1 tf f - f ov se Se EL aS @ i fd z+) Hence, vm e - te ge (1+ & | = alive sign of ma Img Power. inclicates trot ” poll age ln an aps! cee As Inverted. Lungth ob the telescope | L = fa + Ue x For’ Lange mogedyng power, f, must be as large . as possik le and must be as Small as possible. . Hence Mm telescope aperture of objective Auns 4d ’ made Longe tp increase mognifging. power and ALrvlving Power. off the sebocor! Hence | Mmm = “3 Thmax = ~#(! +S) Refleeting type Telescope (Casseqrainian Telescope) ~ Tt BS an rm provernent over the vefeacting. ype Arjescope » objective Aink is veplaced by a Cencave partbolic “mirror of loage aperture, which A free. prom Chromatic anol sphenicod aberrvehom- The. imagé fowmecl ig much brighter and the ~ reflecting type “Feleseope hos much hight resolving power Compancel He refracting Hype teleacope- Suth a telesce pe 4& Known ar Camegrainian telescope on the Yarnve of Ads inventor: . 4 ‘ A replectin pe telescope wos Alsipaed initially by Newton gna modiftedl by Cosseg rouniian|, 7 | OBJECTIVE, / MIRROR (C) —> LE __SSSSSS) UVLS ANVLSIC Woud SAVY TJaTIvuve YOUMIN , AXVONOOIS XQ EYE neal SESS) | In HAlagmm C uw 4 parabohe concave. veflector of about 200 inch apertwe with a narrow hele at the ‘ centre. Pasxathed) Tougs pom a dutant star entering the « telescope In a deectin porate) to pamcipal axis of thre mivror tend fo Collect at the focus ph the mivor But thre vehlected| Yous encounter a secondary Convex wirvor B before meting. Ot the focus The Convex mirror veflects them onto the ee piece 5 and the final image. is sean through the eye plece- The. fined image a@& seen buy the e piece ib invertect gee the olgeck. o eo P In normal adjustment , magnifying power ok a reflecting type Felescope is given by - m= se - Ala fe de : Where. 'R ds yaclius of Cumoture of Concave reflector. Pe, Newtonian reflecting type Telescope- The Poratlled beam oa Light Ceorhimg +srorn. the istomt Stan KA veffected by lange paral 8 Cencave veflector C on to @ plane mirror M. Thu mirvov JS inclined at an angle of 45° to tHe axis of C+ TA. plang. mixrow reflects Hac beam forming Qa veal image I in from ef an eye. piece E- The eye piece acts ask a mammifier and the fi al virtual) and magnified image of the Star is seen distinctly by the eye. Advantoges- C1) There Ys no chromatic and spherical cberration clue 40 Use of mirror objective n place oh Lense. (ii) Tmoage as beughter as Comparca Ato refracting type teles@pe. amo igh retolution us acheivecl by using aA mirror of Lange aperture . ae Tre objectve of an astronomical telescope has oy ameter of {s0mm and a focas Leng of 4m- The eye piece hos a fecol | Lungth of 25 mm. Find the mognif ying and resolving power df telescope (A = 6000 A for yells Colour) * | : Sel; Given thet - foc 4m. 5, t= af xis?m. “4 De 2sconN = O12SM, ; mngritgng Foo (im) 2 ~Ae(14 §) - -_4 asxie% — 4-000, 11 m = es 1 + Ale 5 2S AIS ( “Orls’ ) ae" To m = —LT6 esolvin - + 2 _D_. R ig. Power. ae * Teen “3 = _ASOX12 tas xid P22 xXexpo’ Resolving Pomey = 205 x10 q) A smotl telescope has an objective tens of focal rest Aungth {so tm: and an eye piece of focal dengtn *" Bem. Th this. telescope Ja usecl ao view @ loom. hr tower BKm. away > find the hei of the fined image wher JET ik feoxmed| 25m. away frm ° the eye piece. ‘ Sol Given theat- f,= Isoem ., F, = 5tm. v e > Drz25%m- Magnification m- “- (1+ £.) me “EVE 2-8 Lest hes gd of fined mage uA h cm. v. tomfe = ah B= Visued angle formed by 25 firel imoge at exe.  Joo i ( = Visual angle subtended amd tom a= Zoos ~ Bo by object abr objech ve | But Magn idicatimn Mm = ten a : tan o & —36 = ( Yas) = Roh si i ‘ 1/0) 2S by hos -=BEXES = - 3ocm. 'B3o Hex negative sign rndicates the inverted image -