Reg. No. :

Nu-":,..-L....Second Year

- M

^tch 2012

Code No. 1015Fot Stheme-I Candidates

Time : 2 HoursCool-o{f time : 15 Minutes

Part IIIPHYSICS

Maximum : 60 Scorcs

General Instntclions to Canrlidates :. There is a 'cool-offtime' of 15 minutes in addition to the writing time of2 hrs.. You arc not allowed to write your answe$ nor to discuss anything with others dudng

the 'cool-off time' .. Use the 'cool-off time' to get familiar with questions and to plan your answers.. Read queslions caxefully belore answering.. All questions arc compul$ory and only intemal choice is allowed.. When you select a questiorL all the sub-questions must be answered fiom the same

questioh itself.. Calculations, figues and graphs should tle shown in the answer sheet itselfo Malayalam version ofthe questions is also provided.o Oive equatioru wherever necessiuy.. Electronic devices except non-prograrnmable calculators are not allowed in the

Examination Hall.

rn'klcg

l. (a) Name the physical quantitywhich has its unit joule.coulomb l. Is it a vector or ascalar ? (l)(b) Tuo plane sheets of chargedensities

- o and - o are keprtn ar as shown in figure. Whalare the electdc field intensitiesat points A and B ? (l)

(a) The resistance ,R' of aconductor depends on itslength ,/', area ofcross_section'A' and the resistivity of thmalerial .p'. The corectexpression conaecting R, /. Aand 'p,is

(q R=* to) R=pA/ (1)(b) The voltage-crment graphs for

two resistors of the samematerial and same radii withlengths Lt and L2 are shown inthe figure. If Lt > L2, state

el,ra, eltbdffif qol6rD1do9o,

"o'lrulood e,rcenEsf,Qra)Jos aql6@"Jd{!!l po;6r(0] ooqooc, miqeetaoc ? (l)+ o.

- o 4tcdsd oaod(rulolColgg o6n5 nuar..roer6doirA

"Jlt(d)(drol(d @,c6ml.m.o)-cnjcoer ia,q1@,o,l9Jlo.l6ot(IDl.oO, 6DI norrDl enncnliogfi_e,Jgg qerlq'ld o.ol.druioood)caot@ldoto ? (t)

noJ atcer@,oloiloal ooc(Do(R), rooorfoq rnrg" i4,5,*ff;3,,,H*?ffi,$J;( p) o0firrloj@)o?col ml(n-or_ogsiloldoJmt. R, /, A. ono.rrt.ll (or@'letgg @ol(a)ca)6r)larr(jjo @c6rrt@oJ(rD m)o_otc6,.\o

tu) R=#(D) R = pA,r (t)

L (a)

o)

+o.B

(A) R=+ re) R={

2. (a,-o

(4 "=+

3. 3.The orderly distribution ofelechomagnetic rudiationsaccording to their wavelength orliequency is called electromagneticspectum- Identify the constituentmdiation of ele4tromagneticspectrum which(i) is used for studying crystal

structure.

(ii) is absorbed by the ozone layerin the atnosphere.

(iii) produces greenhouse effect.L(v) used in medicine to destroycancer cells. (2)

Using the data given below, state asto which of the given lerlses willyou prefer to use as

(i) an eye-piece and(ii) an objective to construct,an

astronomical telescope ? Givercason for youl answer.

ooojBjlo) @,c(ro'ld, @,'lo6rD6dBo8ctaomolos (d,.oo(, oo6d"$(oloibaeGDofl6;1(.8 croorA(dlctaoJog

5. orcog .o(mloloJm 1^rmiocorn-

GDslfiunc(f)oro'iloi t@,o16o14-oilocno)csrd mio"rCq" noeT)]djo@l.m(d. rOCOg .O.rrikololrrDol(Itj(o)lord,glocco'l 5r,loi(Dods6jlo6rn6gBoa

"oorcoemrnl ooerre-oro)6.(i) lelrpon "ers(r) oro'ldolff)ojl-(r}ldceoc(,t@o}(m(d. *(ii)

noo@1@,giolotloer o?c'nrc6nd f f {olcgil GDolo6rrro oorq;cmoi. re5(iii) "oo1o r.lrj"o tolrecotogerecaoymroi. (r V {oq,(iv) 6)6)r)113.\ ,rta,tor"ar.d,t

(c) Alkali metals are most suitablefor photoelechic emission.

(d) Davisson-Germer experimentproved the particle natur ofelectrons.

(a) In the following nuclearfission rea.tion, N is thenumber of neutons released.What is the value ofN ?

]rju + j' -+ lras, +

rr|ox"

+N(b) Complete the following

nuclear reaction equation.

le" + ln" -----+ j" + -- $(c) Two nuclei have mass

mrmbers in the mtio 1 : g.What is the ratio of theirnuclear radii ? (l)

(a) Identify the logic gate.(b) Draw its logic s),rnbol.

(2)

6.

(c) ooncGsc @ettqld t"Jrec.ll_oror'lqi

"0gr4o 6o

lcy'lf this logic gate is connected\'/ to a NOT gate, what will be

the output, when

(i) A= I, B: 1 and(iD A=0,8=l?

8. Materials are classified intoferomagnetic, paramagnetic anddiamagneric according to theirmagretic properties.

,-ktl Which one of the following is

u.b)

not ferromagnetic ?(A) Cobalt@) kon(C) Nickel(D) Bismuth O)Define the term magneticsusceptibility. What is itsvalue for a perfeci diamagnet ? (1)

(c) State the rcason why soll ironis used in makingelectromagnets. (f)

9. The phenomenon in which elecriccurrent is gerc@ted by varyingmagnetic field is calledelectromagnetic induction.

(a) Wlich law helps to detect thedirection of induced cunent ?Slate the law. (1)

(b) Explain what are eddycurrents, O)

(c) Write any two uses of eddycrurcllts. (l)

1015

(r)

(c) pa' cercsld; c('gloc(o).l oolNOT c(,)d olsl*l4c(fl,(i) A=l,B:1(iD A-0,B:1orgcorccd er4'$oj152o,

. Match theB c(i) Doppler ScatteriIrg Theory of

lieht(ii) Maxwell Red shift Coherentsoutces(iii) Ravleieh Polarization AstiFnatism

Diflraction Speed ofGalaxies

Electro-magnelic

Blue colourof sky

(3)

,4nJ. 10. cdd

11. Given below i6 the graph betweenfrequency (u) of the incident lightand maximum kinetic energy (Ek)of enitted photoelectons.

-4(a) Define the

function andfrequency.

(b) Find the values of(i) threshold lrequency and(ii) work function from thegaph. o)12. Nels Bohr explained hydrogen

spectrum based on quantirm ideas.-@ Draw the energy level diagram

1 l. dr(o(r) Lol@,c@@ib(d GOoJ_iool(o)Jo (u) CdqDda.l@oCs).rDcn .)cic gpad,olscem;a,g;o sa,ldoo ('(o)lcelds.lllo (Er)(d)eolel)gg 6nc.d rocoe rormrf

E

6

!zt0l-:

oldol0rrJ.

ofhydrogen atom.Name the differentlines obsewed inspectrum.

tems-workthreshold

0)sedes ofhydrogen

(r)

(2)

B

(a) rrrd@d' onoqt sloA, o(oc.&c_oiojj tonl@roafiul ooqrrlol(Itd.!.jtdo}6,.

e.)(b) CtncooitoE cn

l3;PD/(\oose rhe conecl relationoetween the transistorparameten ct and p.

(A) p=+@) p=*(c) p=+@) p=#; o)Define the quantities d and p. (l)Give their possible range ofvalues. (l)

-.(") Sho* the tansitions betweenenergy levels producing thedifferent series. O)

(c) ryJorJa$id' rn,1o1rru)@,vd@6,6co6lDocco, no(r)rdgl ' oetc!_etlo,uAdolsaoioe, (soqdfiu.l.$c-(rr)@,od or(oei d,c6rrr1@oJe. O)

IJ. (a) q. p Lscoi(rutqlp alo]olgol-6ud @@lelJgg crucicr,o@olaoc(a,l 6c6n @oJcr, filq-Qjc6Jo O.ooo6otosJdo)@,.{A) o = 1-q

ct

(B) p_*rO R =1lgto) p=Ifu (r)

(b) c, F "gXrrnc! d6q.jdot6. (1)(c) oP(!lqr,))os ole{6!Boad6;

o)(c)

14. Spectrum allocations forcommunication are arrived at by anDrernahonal agreement.(a) Narne $e agency which

administers the present svstemof frequency allocations. (l)

@) Draw block diagrams of anamplitude modulated(i) trursmitter and(ii) receiver e)

Fill in the blanks :If'ol' is the angular frequencyoI a.c., then the reactarlceoffered by inductance .L. andcapacitance .C'

are

ou3DJo3(oJ Gooaj (r)oE@,Jo,. (l )

oicdoto)c ojlctoa) GEoJ@J6!BoA@o1.ao)JgE .mjodtqo,

.oa.DJeJrrdol.rD@jcDrro(doqoDlaQJ qr3odlD !ol6g@AC6nj(a)

".EoJ "OsqEqrjla,c6rfi @rmooloCdol@,Jdqul on.oo6r, Co tL@,,}a)oo@,@JcoJo o.rg)lm(oi ? (l)

O) oOoXJtggdcoraDlaerpadtrl 1sc@mlolgrnooficorl(rr ) daulr)lolooiaolo a6Hcdd

eDcoLo6sBs, orcqrdol@,. (2)

r4.

:2 15. fa)respectiveltXL=.--and

ojlscoo or,lotddol@, :'o)' (soo(,)etd Lonld,JaAqDl_

co,lgg noJ oo.aul. (rud6,rr-S]cd eqcdrudgoad L n",@,dcoulg(6al C-cor;o gopc_@ol.D .tqooqotmt o)ncl6,oo^r-=- \=_ (r)l0l5

&= (r)

P,T.o.

ft) Aa electric bulb ,8, and aparallel plate capacitor .C. areconnecled in series as shownn tgwe. The bulb glows withsome brightness. How will thegtow of the bulb affected onrjltroducing a dielectric slabbetweh tbe plates of thecapacttor ? Give reasons insupport ofyour answer.

(b) @erd'Lsld 6rusd6ni B_e)o.6:c,oend odQ, @,gcrnd;L-qrJo

.jto)im)h o,c#l-?qtcnrcoel 5rol do.mj.'ru'ud,Jlslr@ oetslnrld)ol_doJcml. 6ru!66Di ,^

^i ^r-- .,(rDdor$Sitdwed\,r/d. 6r!q,6ru CaJ&CLrO,l,J)-ooc5rEloldolqDl. e4Jcol';aegcmt?d:,!glY:9d 'eol- ooflL-r@erd;(sld;

^r,mifori"J6DJrrd6Dioq t"jan o orf-f L.u_rooaor o{)6gB5)(D 6n cqjildo)o ?gotooo fiuc@l6o.ldo)6,.

(t)

Q)

-6 orr".-below are two "r""r"

(t)circuits A andratio of powercircuit B to that ofA ?

In the potenti ometer circuitthe balarce poihl is at X.

B. What is thefactor of the

shown, 16. frTli$#;"#^s"'#*ffiHe^

t6D6lqDl.

s'

#i3J"$"#''Ts-ffiff;i(a) oogcoDle4o ocealetco(6'_

o{niXprflTo n. oraarrf6qc,rd. '1f .y

(c) d B ooqr,1 o5rd perLe,ld,(ruooJlsJ6q6 @rcoc o6,;sr_:t6to1doJ0D,l. a-o]o.oo,pA_@-los@lo

^lold ^!c&o)6,u1rdr@'rerlgg lEbo,lorc(',o ro;LoForcao,loldo)o ?xL= 3R

X, =3R

l0l5

(c) Cell P is replaced by anothercell whose e.m.f. is lower than

t ofcell Q. o)Yo-}l are asked to compare thee.m.f s of two cells using apotentiometer. Draw thecircuit diagnm for this andexplain how you willdete.mine th6 ratio ofe.m.fs. (2)

17. Oe6tead found that moving chargesor curents produce a magnetic fieldin the srmounding space.

(a) An electric current is flowingdue south along a power line.What is the direction ofmagretic field (i) above jt and(ii) below it ? (1)

O) DIaw a neat and labelleddiagram of a cyclotron. Statethe underlying principle of itsworking. e)

L{6} A cyclohon's oscillatorfrequency is 10 MHz. Whatshould be the operatirgmagnetic field for acceleratingprotons ? e = 1.6 x 10-19 C,mass of proton r\ = 1.67 xto-2?tg. e)

l01s g

(b) R aud@mdol S ollaa&jl4coe O)(c) oouc6 p-dd d@,oq e-oile{od,Jo6rmD p.o6)o.ooo-d. gggosDd aejslileJcd. O)(d) oolcgoaad4cokd

eoro(oc_utd @drBl o(n)gJl@,glosg9o.o61o.o4od o_,co.ooJoo.JElocd rrl6lBogcd Grooj_00j6,,*FiloldolcDl. A(o,kDc(q)lgEau6@,J:5 ctr)(oL('o oocJoo;o.sDoJo.lc@o d{D6sBo(r' 66rBJ_"jldldoloocd ailuD6oc@6,J@,. (2)

"Jejl@olfir, 4lcdsl@,oA GEoS6,1(oEoooroJJ.o {.ojotcooo dlgler}o6cooila, o6rnDeto cruS.Eloel;oocnlncdqllad eo6rBoot.(a) aol orera ooerr1tel,os

ot6rdd' rt@qf d oool6JJ@,Lojrrlort@oJm). lqrd.o.lcDl(i) oJ6Citerlo liit ,orcovo,So6coat@, o6ntDet(ootooe B10ooao.rcotoloolo ? O)(b) ooouqscotsc5rr,loo3 ec(/)-6rBUd GDsaocgodslcolo,la)lgg4flt.6ro olod@ol@' cD(o.rocre(oJCr6orDCf, o)orJo oiooR_oc@o]6. Q)oofiuc*co(sc6ntocra acaD}'oeigd Ldol@,rdcu,l l0 oo(,coooddad cD6lfiD). atoJcosc_6ml66)9 cpdmercogJo.Jgcd @rgox/oJo9@ ecoo.teooru(('}G ool(oaocadloldolo ?e = 1.6 x 10-19 C, cLdJec5c6naqc(rf\= 1.67 x 10-27 kg. (2)

O) Resistance S iskeeping R constani.

increased,

.(l)

I

\l'7.

(c)

P.T.O.

18. A spherical surface of radius ofcurvature R, sepamtes a rarel and adenser rnedium as shown in thcfigure.

(a) Complete the path of theincident ray of light, showingthe formation ofa rcal image. (1)(b) Derive the relation connectingobject distance 'u', imagedistance 'v', radius ofcurvatue R and the reftactiveindices n, and n2 of the twomedia. e)(c) A thin convex leas of focallength 5 cm is used as a simplemicroscope by a person withnormal near poiDt (25 cm).What is the magnifying power

Iofthe microscope ? (1;)

ORIn the figure PQ is a rayincident on a pism ABC.

(d) Complete the ray diagramshowing the passage of light.Mark angle of ircidence i,angle of emergence e, mgle ofdeviation 6 and angle ofrefractions rl and t2. O)

18. R coortcoo$ acod 66colqolgg5lo) G(ocgo)elq (rDcL(Brodlsl(qJorlo 6,lo6wrorloc(o @c(r).\o-5sBog .jl(@(o('il(S @,c6rTrlcDo)J-cdcoe! c(ll6o)loli0ol@o)m).

(a) ool cncord pco' olo.looecgpc(nlgg txr ar)aoL(,)od1doro,1@co16. 0 )

O) 'u', 'v', & n,, n" goooreruoi

(e) Using the diagram obrainrelation

6=i+e-A(f) The critical angle for diamond

is 30". What is its reftactiveindex ?

19. The idea of,Electric field lines, isuseful in pictodally rnapping theelectric field around charges.

(a) Give any two properties ofelectdc lines offorre. O)

O) State Gauss's theorem inelecAostatics, O)(c) Using the theorem, dedve a!expression for electric fielddue to a uniformly chatged

, . $lslberical shell\',-Vfl(r) at a poinr outside lheI shell(ii) at a point inside theshell.

(e) 6=i+e-A ao.rD cruoryc@(o"ll(oioufl o(d mr.o"coroororcj.

the

rls (h

(d) ^

A point charge of+ lO Fc is atd'a distance of 5 cm directly,, above the cenhe ofa square of

side l0 cm as sho&r in 1igure.What is the electric flux

(D rur(oro6ltskae (p,Ebod c@'16a630" 6D@,JqDJ.

.tto.cd,g.lojgacAou*nd

"0(crorcaotol@op ? O+)

,rc6ssJ@,03dd .4glolgg ooqBJJo)

@5mDejo 4nLor16,o:ldocoA, oootBJJo.,6nJeJcoor@,04' doqD cD('oao)o9nJ@lcOodsJ(mJ.(a) oocuoJyor 6ruet c.o6u6glos

o6oro@,1e{o o5rd @)5rD66BuaooeJ.0,l6. 0 )O) geidctscqlpgl&nirer o@c\.njcnlcoroogotmiotcorloo;o. (11(c) g\rrr$or}o fiilaor@o gojceJo(]lt.jco}6rDlcoogoc{ol

"jcrdsdodgods q$oon.,l@ocdo.dlRboa (i ) arloorolo(ll) raD@,(droJo 6njl.Bl@oglet)_erecoJrm pera,,"Lsld no1

Besides its use in storing chaxge, acapacitor is a key element of mosta.c. circuits.(e) What are the factors on which

the capacitance of a parallelplate air capacitor depends ? (1)(f) Define the term 'dielectricconstant'ofamedium. (1)

(g) Tlvo capacitors Ct and C2 areconnected in series. Derive anexpression for the capacitanceof the combination.

(h) Find thecapacitance ofgiven in the network.

dc{acgd auoeol4oolaoidoJff orl-o(T)s$o oro.rD e'H9(Iulgii 40. rru].(ru(d@,ll5l@,0llos @ol m)]Lolocq,nelsalo 6,)sl@c6nJ.(e) oo;

"jcoeri adg' "O(o)dodc(rulgdooe edo(r\,lAadmjn0oo,Jod6r OXru'or;orOOgcr9(@@14ilo1@FDl ? O)(0'oo(tl)e&{dld eer6r6qBoe"of)oo,cocTDfiri q'd"eldtgilaidl@Fnl. p.9a\.,-o(a,trd,oE oq &rgc(ntgorrul(T))gg m)o.ulelo e6r6rB_

d)ds

(+)

(dnrt6,.equivalentcapacitors

4pF

-l--Ao---J II IFj--i- l2G9ur)

(h) ocoe .dr(IrnololcD (oJooJ-erco,los 6dcaul0d(n; 66rBl-dils'ldo)@,. Clt3pF

1015 t2