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Answer all qilestions.

@'**ec*ion orLight1 Diagram I shows a thumb-tack is placed n front of aplanemirror.

'.f AT'eT'cf'' n

DIAGRAM1At whichposition,A, B, C orD is the mageof the thumb-tack as seenby the observer?A girl wishes o buy a Planemirror that would allow hertosee hewholeof hersplf.f sheis 152 m all, heplanemirrormusthavea minimumheightofA 38cmB 5lcmDiagram2 showsa light raYXY which is directedonto acbncavemirror at point Y. Fand C represenihe miffor'sfocal point and centre ofcurYaMe.

Prineipalaxis

DDIAGRAM2

Whichofthe lines,A, B, C orp best epresentshe pathofthe reflected ay?f4i = 4rJ

I

C 76cmD l52cm

' " '. - I *. ,t ' t ;.

2., ,+.lil' : . ,:1.-.+:., " * . i. . *. " ,*. . j7 Diagram 4 shows a girl

11.:1 t: . . , , r1 i ,

l ' j : . t, l$*sii,Fti i*t. ' , .,:,I,,t.;.,:-i , t. 1:, s ,.'1"r.: ,. ;;,s:,Lbt*.a6ri !,i,ii-&q,ristt :,l.

4 Diagram 3 showsa concavemirror with focal length .

DIAGRAMSAt which of the points,A, B,C or D should an object beplacedso as o producea realandmagnified mage?5 Byvaryingtheobjectdistance,the image produced may bereal or virtual if the mirroruseds aA planemirrorB convexmirrorC concavemirror6 Which of the followinginstruments uses concavemiror in its application?A PeriscopeB TorchC Surveillance irrorD Blind cornermirror

DIAGRAM4The imageseenby thegirl isA lUVW|c lnAMlBlwwl'@

8 Diagram 5 showshow a raysPla of tisht is reflectedafter it*39 6i15f,eplanemirror XY withan ncidentangleof l0'. themirror is then ilted clockwiseto an angleof20o.

4rob l*ti"s ataPlanemirror'

DIAGRAM5What is the new angle ofreflectionof the ight ray?A 100B 15"

c 24"D 30"

,70.

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9 Diagram 6 shows an objectltfj$ placea at a distance, L in front.v ofa concavemirror. Thepoint

marked F is its focal point.Concavemlrror

DIAGRAM 6What are he characteristicsofthe image formed?. A Real, upright. magnified

. B Real" nverted,diminishedC Virtual, inverteddiminishedD Vrfiral, upright,

magnified10 Diagram 7 shows Ahmad

-68Q. takins an eye test. He is madeq!9 ro siiz m in frontof aplanemirror.He seeshe mage fthe ettersn themirror.

DIAGRAM 7If the chartwith the letters s3 m ftom Ahmad, colculatethe distancebetweenAhmadand he mage.A2mC5mB 3m D 7mA basement car park hasl

,r6m( a sham bend as shown inI tiugra* g

ffi'II

DIAGRAMS

Which mirror is most suitableto be placed at P so that bothofthe drivers in car X and carY can seeeach other?

boyofa

o *t"u--o// f l / t / / f

12 Diagram 9'9P!( standing 3 mt3lll ptane,rii.ror.

shows ain front

DIAGRAM9The boy moves m forward.What s the distance etweentheboy andhis image?A 3mB4mC. 5mD6m

@',n**"oorl ot Ltghi13 Aray oflight is incident n aglassprismin suehaway thatthe refracted ray strikes thesecondsurfaceat righl angleasshownn Diagram10.

DIAGRAM 10If the refractive index of theglass s 1.5,calculate he angleof incidence, .a 300B 42"c 49"D 600

17.. | | ,.

15

., i'r,. Physics orm 4 Chapter

14 A slabof glass .0cm hick splaced n opofa printedpageasshown n Diasram l.

DIAGRAM 1IIfthe refractive ndexofglassis 1.5, how far do the lettersappear o be raised up fromthe printed page?A 0.5 cm C 1.5cr nB 1.0cm D 2.0cmThe speedoflight in vacuumis3. 0x 10 8m s-].What vill beits speedwhen the ight travelsthrough a transparentmediumwith refractive ndex 2.1?A 6.3x 108m s-rts 4.9 x 1fl8m s*tC 3.8x 108m s- lD 1.4x 10sm s- lLight of differentcolours havedifferent refractive indexesrvhenpassing hrougha glass.Refractive index of blue lisht=qRefractive index of yellowlight = n,Refractivendex of red isht:n,Ifno > n" ) n, we can deducethat when travelling throughglassA red light travels thefastestB yellow light travels the

slowestC all three colours have the

same speedD blue light travels rvith

3.0x108ms-rThe stars we observe rom theEarth during night, appear tofwinkle. This is the resultofA dispersion f lightB scattering flightC reflectionoflightD refractionoflight

16

t7

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@io,. PbysicsForm 4 chopter

18 Diagram 12 showsa ray ofCfj!) lightpassingromwatertoair.\ i /CB

DIAGRAM 12Which labelledarows, A, B, Cor D shows the correct path ofthe ray when it enters he air?

19 An observer cannot see,9r( the button placed at thel33S/ 66116p of an empry glass

as shown in Diagram 13.1.However,hecansee he buttonafter the glass is filled withwater as shown in Diagram,3,2.Obsener's eye

Jv

DIAGRAM 13.IObsen'er's eye

WaterButtolr

DIAGRAM 1J.2Which of the followingstatements describes thesituation n Diagram 13.2?A He sees he actual button.B He sees a real image ofthe button.C He seesa reflection of thebutton.D He seesa virtual imageofthe button.

20 Diagram 14 shorvs a boy"6P!0:standinsat the shallou'end oiL?00t,\;# a swimrning pool. He looks

straight down at his feet andnotices that he appears o beshorter han usual. ,,

-Ray of light DIAGRAM14If the shallow end is 1.2 mdeepand he,refractivendexof water is f, by how muchwill heappear horter?A 0.3mB 0.4mC 0.7mD 0.9m

2l Diagram 15 showsthe path#ryrar ravelled y aray of light as tQP streakshrlugh a rectangularglass lock.

DIAGNAM15Which labelled parts,B, C or D is the anglerefraction?22 Diagram 16 shows a

-.fflt of lisht as it crosses"d?5"s 1- q"uid oundary.

DIAGRAM16What s refractivendexof theliquidX?A 0.60B 0.92c 1.09D 1.68

1','

A,of

rayan

23@ A ray of light trryels from airinto a glass lock'as hown nDiagram 17. The refractiveindexof glasss 1.53.

DIAGRAMT7What sthe angleof incidence?A 20" C 500B 30" D 60"

Total lnternalReflection of LightThe critical angle of lighttravelling from a particularglasso air is 42o.What s therefractivendexof thisglass?A 0.67 C r.49B 1.39 D 2.01The refractive ndex of wateris 1.33.A ray oflight travelsfrom the bottom of a pool tothe water surface.What is themaximum angleof incidencethat allowsthe ray of light toemerseromthe water o air?A 25"B 41" c 49"D 90"Diagram l8 shows a ray oflightstrikeshesecond urfaceofthe glass rismat acriticalangle f42o.

DIAGRAM IEIf the refiective index of glassis 1.5,what will be the angleofincidence, ?

24

25

A 12" c 380B 280 D 60"

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27 Which of the followingstatementss not describingthe phenomenon ue to totalinternalreflection?A Mirage observed n thehot desert.B Rainbowobservedafteraheavydownpour.C A diver havinga fish-eyeview while underwater.D A person appears o beshorterwhen standing napool of water.2t Which bf the following is due

db ,o total internal eflection?Y -iz-aulass- . | l l rAiilr,W cl(l'tr

Diagram 19 shows a ray oflight passesthroughn opticalfibre.

Liebt tyDIAGRAM 17Which of the followingcomparisonss correct?A Refractive index X >RefractivendexYB Refractive index X =Refractive ndex YC Refractive index XRefractivendexY

Diagram 20 shows a ray oflight travelling from air into aglassprism.

29@

30@

DIACRAM 20

31@

What is the critical angleoftheglassprism?A 30" C 500B 40" D 700Diagram 21 shows a rayof light experiencing totalinternal reffestion whenhavelling from mediun A tomediumB.

DIAGRAM2lWhich statemnts bout totalinternal eflectionareconect?P - 0 is the critical angleofglass.Q- MediumA is denserhanmediumB.R- The speed of light isslower n msdiumA thanin mediumB.A FandQ C QandRB PandR D BQandR

32 Diagrams 2.1md22.2 sbovtdffi1oyr of light havelling from\z glass to air with differentanglesofincidence.

DIAGRAM22.2Identifr the critical angletheglass.Ap CrBq Ds

of

DIAGRAM22.I

t73.,

-u *" PhysicsFonn 4 ChopgrS

@''.r.*to33 Diagram23 showsa convexlens forming a real andinverted mageof a candleonascreen. heupperhalfofthelens is then coveredwith anopaque ard.

opaquecard-\ tT:"n.*o*{ monvexensDIAGRAM23ThiscausesA theupperhalfoftheimageto disappearB thelowerhalfoftheimageto disap.pearC the mage emainsexactly

thesameasbeforeD theimageremainsthesamein sizebut essbright34 Diagram24 showsan objectplaced in front of a convexlensoffocal length, .

l r , I Ii I Vn*c*in+f+f+f+f+DIAGRAM24

At whichposition,A, B, C orD will the magebe?35 Diagram 25 showsa studentusing a magnifying glass toobserve he nsect n detail.

A.P-^>If l .a- t_-__. R

#DIAGRAM25Whereshould hepositiontheinsect?AP CRBa DS

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urdiGi** physlg Form4 Chapter

36 A studentcomplains hat hecannotsee ar objectsclearlY.Diagram26shows hePathofthe light rays enteringhis eYe'

I}IAGRAM26Which lens couldhelp him toovercome heproblem?At7A t l c {(V\B( DflV

37 Diagram 27 shows an objectbeing placed 8 cm in front ofa convex ensand ts image sformed 26 em away from theobject.

Object

DIAGRAM 27Calculate the linearmagnification of the image.A 0.31 c 2.25B A,44 D 3.25A convex lens has a focallengthof 20 cm.Thepowerofthis ens sA -0.20DB +0.20Dc -5.0DD +5.0DDiagram 28 shows aconvex lens fixed insidea cylinder. An illuminatedobjectprodueesn mage hatis real, invertedand of thesame izeas he object.

38

39

ObjectAI

40 A convex lens is used in anexperiment o veriff the lensequation.A graphof j againstI; is shown n Diagram29.

$/cm-'

DIAGRAM 29What is the focal length of thelens used?A 5.0cmB -5.0 cm

41 Agraphoflinearmagrrification,nr"againstmagedistance,, isshownn Diagram30.

DIAGRAI\{30Whichof the ollowingcanbededucedrom thegraph?Tlpq$i leit*' Focalleoglh

Concaveens -30 cmConcave ens -15 crnConvex lens 30crrlConvexens 15cm

,74

DIAGRAM28If the distancebetween theobjectandthemages 60cm,what is the focal lengthof thelens?A 15cmB 20cm

10cm-i0 cm

C 30cmD 45cm

CD

C

42 An object rvith height of 3 cmis placed 15 cm in fiont of aconcave lepswith focal length-10 cm. lVhat is the heightand the type of the imageproduced?

Ileightofimage lFgot,image7.2 m Real1.8 m Real1.2 m Virtual1.8 m Virtual

You are provided with threelensesP,Q andR. Thepowerof the enses reas ollows:powerof lensp : + 20 DPower f lensQ: + 10DPower f lensR: - 10DWhich combinationss idealfor making a compoundmicroscope?

+20D *10D-10 D +20D+20D +10D+10D +20D

44 Diagram 3l shows two,"tf$r lenses.P andQ are ananget33/ 1s function ur a simpleastronomical elescope.Thefocal engthofthe lensP and

Q are , andt respectively.

Lens PDIAGRAM31Which statementss mre?

A f, is shorterhan o.B The power of lens P issmallerhan ensQ.C Thedistance,d,separlensesP andQ is greatethan f, + fo.

CD43

CD

tLens Q

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45@

D Lens P producesa virtualimage while lens aproducesa real image.

An object is placedat a distanceof u cm from the optical centreof a convex lens as shown inDiagram 32. The focai lengthofthe lens s l0 cm.

. J DIAGRAM 32Which of the followingcharacteristics of the irnageformed is not correctly matchedwith its corresponding valueofu?

n/cfir:Charaeteristics'::of$e image8 Virtual,magnified

l5 Virtual,diminished20 Real. ame ize25 Real.diminished

46 A student draws light rays asff$, tneV travel through lenses P,v Q, R and S as shown in thediagrams below. The fbcalpointsofthe lensesaremarked

F.-R*m ?.4 t t l * /; \.-v F -F*V--i"

Which drawing(s) is (are)corectlydrawn?A I onlyB II and II onlyC II,II IandIVonlyD I" U, III and V41 Diagram 33 shows how an,gPr( image s formedby a convexQP r"nJ

orffirir,.. PhysicsFonnr4 Chapter

If the height of the object s2 cm. what s theheightof theimage?A 0.69 m C 1.23 mB 1.06 m D 3.78 mWhich of the following raydiagramss hatofamagnifyingglass?A

Image Object

48@

ABCD

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DIAGRAM2.T(a) In Diagram . ,

(i) draw asmallverticalarrow o representan object in a position whore t wouldproduceavirtual image, ll marl4(ii) draw raysto showtho positionof thisvirtual image' [3 marks]

(b) Diapam 2.2shows hree ypsof mirrors,lQ andR, which canbe it3edo ahandlgandusedby a dentist to examine he patielt'steeth.

DIAGRAM2.2Whichmirror would the dentistchoose?

ll marlrlDiagram 3 showsthe path of a light ray as ittravels from air througha glassblock. The lightray strikes he boundaryof theglassblockwiti aglancing ngleof4lo.

EV,v

(a) (i)

a

DIAGRAM3In Diagram 3, completehepathof theray thatemergerom theglassblock.

ll markl

: . - : : .Tr---* :a_ 'aa l-i ' t ' " r l ' : i -1"*: : ' i - : : : !--- i: :-t t :: :i:-i; i=ji= i:-i-j :1,: : i : ; i i ; ' :1 i .i,;.';1.* -1.i-a*: .;i.-i: . . ' . ,1 ' l ;,- l 'r :l i

Whatcanbesaidaboutthe ay enteringandemergingrom the oppositesideoftheglassblock?lL narkl

(D) The refractive ndex of theglassblock is 1.5.Calculatehe(i) angleofincidence,

[2 mailrs](ii) the angleof refraction.

12markslA ray of light is incidentat an engleof 50o atthe midpoint '0' of the plane surfacePQ of asemicircular ce block as shown n Diagram 4.The efractivendexof ice s 1.3.

(a\ (i) Calculatehe angleof refraction.

. lznar$)(ii) Complete the path of the ray inDiagram 4 to show how it emelgesfrom the curve surface.

[2 marksl(iii) Calculate tbe critical angle for theice-airboundary.

:l!,:iiIt\ ig

(ii)

DIAGRAM4

.,76 i

[2 narir-l

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(D)I

Diagnm 5.2shows hree ypesof glassprisms,P,Q andR,

AFxF\,d* uo\ [n\ l-' -XQR

The ray is now made to enterthroughthecurvedsurfacen suchawaythat t strikes heplanesurfacePQat O. Using he appropriatevaluesof the angle of incidence,draw thepathofthe ray in thediagrambelowfor thesituationwhere heangleof incidence(i) equalo the criticalangle,

[2 marks](ii) greaterhan he criticalangle.

[2 marks]Diagram 5,1 shows the structureof a simpleperiscopemadeof two prisms.

LiSht ----->-rays ----+-

bt"DIAGRAM5.1(a) (i) Describeone situationwhereyou needto use aperiscope.

U mo*l

DIAGRAMS.2(ii) Which glass is used in a periscope?

$ mark)

ul@i*u Phyrlcs onn4 Chopur(b) (i) In Diagram'5.l, complete the paths ofthe two rays through the periscope tothe eye n the Diagram5.1.

[2 nark](ii) Name the physics principle that youapplyn s(r) (D.

Is the imageinverted?I marklformed upright or

I marklTable6 shows he lenses hat areavailable n aschool aboratorv.

fypatrhta ,

Nunrbcravafl*treConvex ens 50Convex ens 20Convex ens 5Concave ens 20Concave lens 5

TABLE6(a) Which two lenseswould you choose oconstructan astronomicalelescopemodewith maximummagnifi ation?

[2 marks](r) (i) Draw a ray diagram o show how thelenses houldbearranged ndhow theyfunctionasa telescope.

[4 marks(ii) What is the lengthof your constructetclescope?

12marksCalculatets linearmagnification.

12marks

(iii)

(iit

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