
	Trending ▼ ICSE CBSE 10th ISC CBSE 12th CTET GATE UGC NET Vestibulares ResFinder

CBSE Class XII 2014 : PHYSICS

15 pages, 118 questions, 23 questions with responses, 23 total responses,

	cbse12	+Fave Message
	Profile Timeline Uploads Q & A

Home > cbse12 > DELHI LOCAL Question Papers : CBSE Board Class 12 > F Also featured on: njoshi1971 sunil381

Instantly get Model Answers to questions on this ResPaper. Try now!
NEW ResPaper Exclusive!

Formatting page ...

ilil*,. 55llll Series : OSR/I +f,=i. q{ rq{q Roll No. . o o o o fuf &rd 5q-Ys r Candidates must write the Code on the title page of the answer-book. t Errqrql"qord togs rrlrr-s,r { Eiff gw ls s{trr-{:r it Erk+ wr +1 erk flqq.rqstsrqr *t ur* gtr-gRr*,r * go-ysqr grffit frq or ti t*;gq q'{ct-rr it so q{.T slrTryFrsTssqfrqrilvgsuri.rirrEd, gsrq.rxrrt6. wqyqffi r t r leri r r gtYFt-rl,tft'rqdi+fuq 15 fo{e*.t{rrrittqqrrqrt r qw-q{*rfl+ffiurFiqril to.ts qi tsqr qrftn I 10.15 Tq t 10.30 qQ ro on i;+e qFr-rr s) qilri E{i crcftT *^ +{T A "ilr e+r giw*l qr *t wn qrT fui,i r r o o o o Please check that this question paper contains 15 printed pages. Code number given on the right hand side of the question paper should be written on the title page of the answer-book by the candidate. Please check that this question paper contains 30 questions. write down the Serial Number of the question before attempting it. Please 15 minutes time has been allotted to read this question paper. The question paper will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the question paper only and will not write any answer on the answer-book during this period. dfrofTdrrC*erfun) PHYSICS funfu 42{ : 3 Eitl Timeallowed:3hoursJ (Theory' , atfti*dq eir : 70 tMaximumMorlcs:70 vrqrqF*sr: (i) wfiypq atffit r (ii) wwrwilgaso rwf (iii) (iv) (v) sstttt airwt tsnr t dr a*- ivw etfu-@qrFrf,*pqeb r+. t wr 9 dra C sdsew qt ii w * sfl tg d zz I sA6wq dTr ei w *dqr sw 2s d 30 if ydqyw frq etiow t r dT+ ffi dd wn C d <'a fe al?nfTd rv-+ * I sFr-w t aqrt q-* *H fuw re? * r dqtfu, El dirit zrd w srr i d?q tiof ad w r*r C.ril?- qfu eliqt qd dH wit if atrafwqw yqrq fuqr rqr t / dd fi"ri t oilw] r?+r/d qqitt d#dir qaeqrf,arz* I I 1p.T.O. (vi) *e-fd-cr # sqlrr (vii) Brzqirr wsol t *? etflfu d? x r aq tfu qfr erwqq al al ew Wrudq avot w t qai arnvqq al ew c:3 * Wafud qtfrr fuiq;f n qwf w aqqlq +r nrd' * , 108 m/s h: 6.63 e.: 1.6 x x 10-34 Js 10-19 C $o:4nx 10-7TmA-l -;-:9 1 +TEEo x 109 Nm2 C-2 m":9'1 x 10-31 kg General Instructions : (i) (ii) All questions qre compulsory. (iii) Question Nos. 9 to 18 carry two marl$ each. Question Nos. 19 to 27 corry three marks each and question nos. 28 to 30 carry jive marl<s each. (iv) (v) One of the questions carrying three marks weightage is value based question. (vi) (vii) There are 30 questions in total. Quet;ion Nos. questions and carry one mark each. to I are very short answer type There is no overall choice. However, an internal choice has been provided in one question of two marks, one question of three marla and all three questions offtve marla each weightage. You have to attempt only one of the choices in such questions. Use of calculators is not permitted. However, yott moy use log tables if necessary. You may,use the following values of physical constants wherever necessary : c:3 x 108 m/s h: 6.63 x 10-34 Js e: 1.6 x 10-19 C Po:4nx l0-7TmA-l I -;-:9 +7t,eo x l0e Nm2 C-2 m.:9'1 x 10-31 kg 55nn I 2 1. ffi qra-oit eTr+{r qrqit+t rrhrff,m qft qRqrqr tdfuq r s{r"Fl s.r. q-rs'tmfug I Define the term 'Mobility' of charge carriers in a conductor. Write its S.I. unit. 2. ffi qre+.rnrr C(t):2 *i qg lcrrcarff fq'qr rrqr t , sin (8nt) volt. msdq fu'{f, qvtiq q-flr{stte,t d{'r t I frgdr qrsi*.{m *ifuq m(t)+ it r tQ-+.cif The carrier wave is given by C(t):2 sin (8zrt) volt. The modulating signal is a square wave as shown. Find modulation index. m(t) in volt t in second 3. fi oTraqr frq-{ +fuq, ffi tc- t rffli E]_dr t r" q{ qelq dr gk*ifrq o'fu.fr q-61, qqfuqq ysfuE-d q+{ + sffirmq{d r "For any charge configuration, equipotential surface through a point is normal to the electric field." Justifu. 4. uuil-{ Hr{yr * q{fl.r{rqq-i t (s{r qiq or t, W Fq t qqn st{ {r riltrs qrfi qrqrd q[+'r eY{Bif r qt ,iltrs, Fr+ri \,-*- qr{ 6T r erri t f,srT ffi t qq-fr Two spherical bobs, one metallic and the other of glass, of the same size are allowed to fall freely from the same height above the ground. Which of the two would reach earlier and why ? 5. qrs'if nm *-q-or tsq it +lw CTt-il si qftrirrs-dr m'r kqrur tprtgq r Show variation of resistivity of copper as a function of temperature in a graph. 55nfi 3 lP.T.O. ffi rt-o af{ +i ffi vqo-o E{rr +sq#i[ rer rrqr t gq {i+fi *'erq{ q{{qtqt t 20 cm Xt qrfis-d ffi ffi*-n frq sr qfrkq ES kq *rffi t itq 6t st*. 1t wr tr 6. r r I A convex lens is placed in contact with a plane mirror. A point object at a distance of 20 cm on the axis of this combination has its image coinciding with itself. What is the focal length of the lens ? fq+iq qt B { 7. tt t*qmfrfuq ffi sTra{r * qnq +'r V t.rfuqn r ss gq+iq eia +i fq{n Hr t ? diz-s glq+iq {d F +fuq t Write the expression, in a vector form, for the Lorentz magnetic force charge moving with velocity magnetic force ? F due to a 3 in a magnetic field d. Wnut is the direction of the ++ fmlfi qrq-o{qrcqq Tr *.r Ri-s'oTn-q Rqr rrqr t strq*r+r sd frfiqq 8. qfl+n Fq | 'x' ERI qrqikd ffirqq 6i qcqrnu I wqlrrI o.df rl-JI qs{rqt-d frt*o. {i{r l{,r-d The figure given below shows the block diagram of a generalized communication system. Identifr the element labelled 'X' and write its function. - - - - - -l t- - - tl Transmitter Receiver I Message 9. qi t Signal t 'A' ft1 srik*- SEwflGdT qm. t go aftro t, sqfu 'B' ftt qm,'t | 'A' eil{ 'g' qqnfr fti q-fid qEqrt+g r rq rqrqT +i gq-+tq u-qfu q-ars*..ffi qenr gq*iq m.q Message Signal q-qprT fr auner*'? Out of the two magnetic materials, 'A' has relative perrneability slightly greater than unity while oB' has less than unity. Identiff the nature of the materials 'A' and 'B'. Will their susceptibilities be positive or negative ? 55nn 10. ffi\r*-sqtqfrgilqt{*l B:5 x 103 iNtc ERTdFkTf*rnrnnt rgseh+-Esww*t vro+ifqq=il tO cm TEI+q,t* sqq-g4tTqfirt ks-srdet y-z66rtsqmqt rqfr d?T x-eIQI t 30" ur +tq mrm t, di {S e,i t {-qql qrd.mw $t qrq wr d'n ? 2 : Given a uniform electric field B 5 x 101 i N/C, find the flux of this field through a square of l0 cm on a side whose plane is par;llel to the y-zplane. What would be the flux through the same square if the plane makes a 30" angle with the x-axis ? 11. *ffi *fl *. qftwq fud q,1pry . d* \ rR GFI-itT t -\ r qfi ^ \ rR ErI 'a' {fr *- frr+q qd qi qaffi lslait +r ^^ l" + frhB; * a ets qt r'*e kfr + feq )" ilr'r*{ \rsquf q-fiRr ? t"f"r t sEqsqruil 6{A I Eqrcfl *ifrq For a single slit of width "a", the first minimum of the interference pattem of monochromatic light of wavelength )" [, I occurs at an angle 2 a of ;. At the same angle of we get a maximum for two narrow slits separated by a distance "a". Explain. 12. q{iq.rq+-ct *.rq+qq *.fmq{ffiqrn qr"ft frfuq I vt fuf *.qrq frfuq r Y' flqq.rq qfrqq lekq it p nen e ERr eiim.-d dtrofui si qcqrfrq r qs riftr+ *.fuq {rerltFr {R"ft r A B Write the truth table for the combination of the gates shown. Name the gates used. Y' Identify the logic gates marked 'P' and 'Q' in the given circuit. Write the truth table for the combination. A B 55nfi lP.T.O. 13. ffiF frqq fufuq | {ieiq n[ qrqr +ifrqfu n' Frqq t*.s u-+nqrircirrd t r State Kirchhoff s rules. Explain briefly how these rules are justified. 14. q-{sr ffi qRqP{ i[ ac tq * qreT *uftffiq if {qrird 'C', qfiffi qftrftrr 'R' HeT +t$ qG 'B' {qikd t r ce g;s qrro * srpr qcrf,r t r qk (D qftR}ro R *J vqn {GFR, {qrlu +t qporeit + +q stt q{r+qd qflr*r ro fr vq, (ii) qrkdr +} qqn IGFF{ qftrftrs' n ti gkq'r fr qrq, d qw +t qqcntf wr qfisd-q tt'n z qvtiq oB' are connected in series to the ac mains in circuit as shown. The bulb glows with some brightness. How will the glow of the bulb change if (i) a dielectric slab is introduced between the plates of the capacitor, keeping resistance R to be the same; (ii) the resistance R is increased keeping the same A capacitor'C', a variable resistor 'R' and a bulb capacitance ? Mains 15. urr-wt-{{ sT {f, kcr< fufiqq I {iqtq it s-dq dfrq of eq 6qt +kqekd q.{i it t*- ronfoqr qrrn t l*- qs qqft{ sr Bq+r oTrdiflf, suit r State the underlying principle of a cyclotron. Write briefly how this machine is used to accelerate charged particles to high energies. 16. 4 cm uqr{'+ ffi ffi +qf, e'W *i, qe \'cn-sqr frW qia it qs r*r {qr qrf,r t fs' 60'q.r +tur cffiq, d6t {6Bqq +rF Nm *'ca snqui sT q$Td q.rar &T{ sT sIqT qtd t qkqq qr enfu + 8 nc t, ni gq BTd +i fuTftrq s-qt qfiroftrd +ifoq t r t An electric dipole of length 4 cm, when placed with its axis making an angle of 60o with a uniform electric field, experiences a torque ola1[ Nm. Calculate the potential energy of the dipole, if it has charge +8 nC. 55nfl 6 17. ffi qtin qt{ffi E{-c-tr *t qqn c+cofrrre irs Hfud fl+-qr rrqr t r t u +it { (a) ffi {qq ae-qr'ffi nt rh{ "il qH eTFr*. $t'n, st{ (b) frnssrri*'rsqrt'n z effii En sl mnq qkf, gfu silqq A proton and a deuteron 2 r are accelerated through the same accelerating potential. Which one of the two has (a) greater value of de-Broglie wavelength associated with it, and (b) less momentum ? Give reasons to justify your answer. 18. (i) ffits{HRr 6.0 x 10la Hz e+ffiq.r\rs-dufrqtFl{rBirI=Ifu'qrrrqrt rerokovrlm $T qm 2.0 x 10-3 w t r et-d Hnr *str{ sh t-du-s grukd s}dFit et riqr mr 3rE5eH+1feq (iD (i) r l*.S frq rrg ]rtFI{I gurct ys w fr-qr'r+iwft+qr-mrnwdtqq eTrqfuf, ftfi*-r"if t rorvr *qd *rRr + +q z Monochromatic light of frequency 6.0 power emitted is 2.0 *t frddr *r x 10la Hz is produced by a laser. The x l0-3 W. Estimate the number of photons emitted per second on an average by the source. (iD Draw a plot showing the variation of photoelectric current versus the intensity of incident radiation on a given photosensitive surface. 19. 6qr t, q.{i + flaq tz.s ev * ..aqt* qrqq t6.s s-Et kR irs Eikfr fi ? irFT q{ tfrq trlgiqr dretq doft +qcd rR qrqrfr rg-{FT d?Tr qrrt {@.{ !F o.r Bqqtr t*qr .rqr ffi +T{d s{s ft1d@d qfrqfud *1fqq I A I2.5 eV electron beam is used to bombard gaseous hydrogen at room 3 temperature. Upto which energy level the hydrogen atoms would be excited ? Calculate the wavelengths of the first member of Lyman and first member of Balmer series sslut 7 [P.T.o. 20. ffi xII +t spn, grtflr +1qe r{fld g rT fl*.ss*nmFft erq} Tfl-{ of ua si d-ot{d q.qfr +i l+-{rq.n ti st qlqqT wr G d} ssi gs*r Rr t*qr r Bsi oTqi qrdr-frdr 6} lro flqq-dr EFr $r-r+rcr trqrur tsqT fl*. s{h tsr qri T{ Hr q {Eifrr-d ri+a ysq Eh sil{ us* qror-fqor sc$ varn d.rq s{rdrqiq sH+ ti rlqw *.q* Er{r iqur-z1-{r r*nkd grrr Fn zT + frq (1) sqTr t ffi ' ffi qrkqlTs.fs-q q-fl-{E} qsdr t 3 z (2) sTri qrdT-frm + q)_fir qr Rr *G.V+" i fln.s qe oi e-qfrrd t*qr z (3) 20 m ffi *. ffi q-+{r il-{r ffi qFrg{ ffo fueF gqdrq ilfi nkd *t qr rrs-fi t, +ifuq | qt *t fi-qr = 6410 km) When Sunita, a class XII student, came to know that her parents E{-sr srFFrFT are planning to rent out the top floor of their house to a mobile company she protested. She tried hard to convince her parents that this move would be a health hazard. Ultimately her parents agreed : (1) (2) (3) 21. In what way can the setting up of transmission tower by a mobile company in a residential colony prove to be injurious to health ? By objecting to this move of her parents, what value did Sunita display ? Estimate the range of e.m. waves which can be transmitted by an antenna height 20 m. (Given radius of the earth:6400 km) of ffiqPFflqt+c{* t madnnm.ryftrtq 10o t r16}tutr#qiiffi6vfttffisfu s o +qfuNr*.t {qifua t rsq qprfro.t-i{*1 emf foriftc +itqqS +o cm wriudr kgu-qno,nrt r 3 A potentiometer wire of length 1 m has a resistance of 10 Q. It is connected to a 6 V battery in series with a resistance of 5 Q. Determine the emf of the primary cell which gives a balance point at 40 cm. 22. (a) ffi tfm rTqikd qmqrtr Enr ilikq detT FIq t*tur qto eiHq q-frrvr qfrkq flqq-dtrq $ w qaqr ffi{ + fuq r rtt{-firErtrBilq oTrqf{ s t rgs qq{q{fr *,i ffi frfr-{d qql q{ stsisd t*'qrrqr t r erFrq{qs sid itf,sr + +q s1 nfud Ert 14 cm t r qk FTs E{irf,r + fuq srekrT ffr zo cm d di qFr6qo. sit{ ifi-*l*1st+.s$qRqf6dsitqq r (a) Draw a labelled ray diagram showing the formation of a final image by a (b) ffitg-m{qlrqfiHmrfl=Tgn eTrqf{ 20 t compound microscope at least distance of distinct vision. (b) The total magnification produced by a compound microscope is 20. The magnification produced by the eye piece is 5. The microscope is focussed on a - certain object. The distance between the objective and eyepiece is observed to be 14 cm. If least distance of distinct vision is 20 cm, calculate the focal lenglh of the objective and the eye piece. sslUl 3 23. (a) st{'d-{-{f, st{ ffi s6Fr-dT (b) t gsor qfrfuq t I E{FrT + gw arr *. er1ffir wr t r ol-gffi eTltq +1 qfir qflf{q I ancil ftifuqto oTr*h q6-sqn wit roIt t ys HT tflf,r erTtlT qrt ffi qqRqvrT qqr*i t fuq +qfrkq q{ .Fn q,{Ie q}rn ? EIr fi *iHq I -lq Hifuq ffi sr+ilf, E{rr + aofqqr rrqr (a) qckwr qfrr ffi q{rc-fi 3 A mobile phone lies along the principal axis of a concave mirror. Show, with the help of a suitable diagram, the formation of its image. Explain why magnification is not uniform. (b) Suppose the lower half of the concave mirror's reflecting surface is covered with an opaque material. What effect this will have on the image of the object ? Explain. 24. (a) ffi snAftrf, {rrrmr qQ-{r dfeq (b) ffi + {qri ii sfr q*,rt oTrqr+ qsrfua o.qi + fuq Eistr vrq r rrqFff sr{Ryr +fi-trrfrqd qia "Fr rrFr p t r q< snikncrr({ sil-&r q st lh olri iit*qr rrqr or{ ura sitqq | qftm.r ffi {qrFH a bcda 3 +++++++ ar+b dl--Jc lllllll srelt[t (a) ffi sqrqr qttfir {qrRr qrkdr (b) ffir qflf+.r mr *.kqaiq-*.agirq ;alFrq et{s A ileTr qitfircit ++q IPI-sr d t, ei {qlt{d fo.qr r Rr der n, trwreif + qi oTrnfrH ,fdq qmqit +t qq ffi qre-o f,rr HRT t, d i m.qu' qr (teu q2 sr-+yr srka +r AA t I {t qrf,si st kqrcTt + Er+ ydq sTr&r tr{cii sr eqqrd ffo *ifqq qrar q<t { r (a) Obtain the expression for the energy stored per unit volume in a charged parallel plate capacitor. 55fin lP.T.O. (b) The electric field inside a parallel plate capacitor is E. Find the amount of work done in moving a charge q over a closed rectangular loop a b c d a. ++++ !lllrrr OR (a) Derive the expression for the capacitance of a parallel plate capacitor having plate area A and plate separation d. (b) Two charged spherical conductors of radii R, conducting wire acquire charges q, *d *d & when connected by g2 respectively. Find the ratio a of their surface charge densities in terms of their radii. 25. (a) qm +.rt gq tiqq{ m.r qfrwftq frqq frfuq (b) Rqm dqri'+ qi dd rrrrqT f+gn-ir"fr ri+{rls sr fleTr S, fu { E{iq Qr1-sn vs-({t * sq{ ffi t I slt p{* sT{r .(I,, qtilfr ddq{s Sr t {s+ {qtfui B iFr rdrkd qrrFs?rr sq if I t q) etrfr Ririr+r{s s2 t ridfuf, tmn ffi qqn rrRr ffiir tq{n fr u-{rkd 6t*-r ldr e t qret sTrfi t I qk flii qfr {nri' Eqr-$nizt qt tqr n, ipr q t fi t0 orqr q{ ,fra-r rrqr (iD {Tfi flTflq * qr6{ ffi t{ rR gffi gq-drq t* or qftqm st{ rc1': Ei-fr fqvnxn+ifqq r nz ssfin att 10 (a) State Ampere's circuital law, expressing it in the integral form. (b) Two long coaxial insulated solenoids, S, and S, of equal lengths are wound one over the other as shown in the figure. A steady current "I" flow through the inner solenoid S, to the other end B, which is connected to the outer solenoid S, "I" flows in the opposite direction so as to come out at end A. If n, and nz are the number of tums per unit length, find the through which the same current magnitude and direction of the net magnetic field at a point (i) inside on the axis and (ii) outside the combined system. T h2 26. f+qffie-a q'strfrkq turns : (a) Br +q-d Bq-"iq ni.it or qH fufuq qi tsrc q'nfuit tt qqqm BqTfit rq-{ct if mr sTrgrfuqnqfukq t (b) qt( Tqt rR qrgqu-sf, n *il, d q+ror slY{-d ydq f61 oru-+r.Frr ? E[Gtt qifuq crrrT srrsT {qrn{ it sqt'r * fuq * nrq +1Ee-tr it olftr*. r (c) +t$ aqd 1rq-*lq fli.r fuq gfuqfrHq s{ItkFt ml-tr t, u{ w t I Es+1 in aircraft ErE oTRllv-d +.rfr r Answer the following (a) ys w : Name the em waves which are suitable for radar systems used navigation- Write the range of frequency of these waves. (b) If the earth did not have atmosphere, would its average surface temperature be higher or lower than what it is now ? Explain. (c) 55nn An em wave exerts pressure on the surface on which it is incident. Justifr. 11 lP.T.O. 27 . (a) iHrEf E elTdr *.fuq *'fuq aiw+., N - No e-xt Eilq +Tqq (b) (i) u-fr+rcqq sq fr ?i.r" qltr*lq qiffir (ii) (a) mr W flq *'qr.qro (F*) qrq efitq fr *Teq qlflrs. "* ffou *t qtsqr qi qm +ikq I E{ erq +t ao t mr {{ {rfrs.t erer* qqqrfits. r N: N, e-rt, for the law of radioactive decay. Deduce the expression, (b) (D ++a t Write symbolically the process expressing the B+ decay of ]ft'{a. Also write the basic nuclear process underlying this decay. (ii) 28. (a) Is the nucleus formed in the decay of the nucleus ?fou, (i) '* sda qs-{"fr u-*rvr *a qftTqrkd qftT*-{ur H mnur (iD {frq * ss*r isotope or isobar ? ruT m.r v*-t l' {sor I *ii t sflkd vm,rvr ntd ffit r$-qt crt slr-qrq a nen errgh t m* ie-gw otqrnquT m.rfr t qfr{t nirit *onur fuerrm yl: dcos art itql qt m.mnid{rorvr ro r y z : d cos(ort + O), Tdi 0 +it + +q cr?lt<R t, Ei, ni Es fu q{ qfisnfr frrdr +floqdq-+.qrqil qfrkq (b) .iT +Bfurfr u-drr, m[ r ]., o'.irr*d +\'fiqrtr t, { G +ffi w qd w wTrf,{ x/3 qcFRI iFI sqqtrr floqt rrqr kg, fus r{ ssrmr 1 }, r+rvr +t fi-{dr K qws- t { uorustdeiTrffi*ifqq r fl+-S kg r 3wt.tr (a) BqTff sli-q +t sfl-q-aT t qa Ad ftqfird qld{-{st fqri qr qt*a E} qrnr t (b) st* q"{fud utrnr g-q ffi fl+-qr qr {rFdT t f*. i-{fc-d rorvr z oiq-qrg srf,{rgw.n enqfoo t r sqgffi fu{rr siltq t wqvrtqqt*"gq eranrg$t q{rcffi-d str[y[, qk rr: tan i, t, d {tid' tldr t, qd p *iq sr qrg +qrie{ s+r+f{i*.'dsil i, qer*tur t str.rff ffi *i qtq-d r (a) (D 'Two independent monochromatic sources sustained interference pattern'. Give reason. (ii) Light waves each of amplitude of light cannot produce a "d' and frequency "rD", emanating from two coherent light sources superpose at a point. If the displacements due to : andYz: a cos(ort + $) where Q is the phase difference between the two, obtain the expression for the resultant these waves is given by yr a cos ott intensity at the point. 55ll/l 12 (b) In Young's double slit experiment, using monochromatic light of wavelength l, the intensity of light at a point on the screen where path difference is 1", is K units. Find out the intensity of light at a point where path difference is l,/3. OR (a) How does one demonstrate, using a suitable diagram, that unpolarised light when passed through a Polaroid gets polarised ? (b) A beam of unpolarised light is incident on a glass-air interface. Show, using a suitable ray diagram, that light reflected from the interface is totally polarised, when Ir: tan ir, where p is the refractive index of glass with respect to air and i, is the Brewster's angle. 29. (a) ffi tt vrf, trdrr (eTeffi tsq1-6mT9 qr quh drkqd zrcE{li-dr tfl6t6fr Sre-S d nRf, flqq-d qr6=F wr (emo d f** qtq {s u-*R *tr t t+.qc tst qru Em=r o-ri *r v-qrq m.{fr t'il s$ sfl=r *.{i qrd 1q-+iq IFFRI itqfi:{dT *r Hq qt r (b) ffi ft:r fussr ilcse L t, t frq{uit d qvn+ *.fuqqrrdfuq rrdrkd qrr il t{r<R qk Et rfr t t tTqhfud : O Tqdrqwr.Rr *rqnr-#+q (ii) iko emf eftr dVdt *'*q (iii) {rsf, grqqilq i.qidq u.qi etn qRr s'Eirq [eFn od gu ffi ac qfu* ;nr EIEr rT sflf.q diqq I qs+- otffi ksffi sr {iqtq it sdq siti{q t fu-S goq+iq da { q'ir s{i qrd ffi Efq rqo qf, srqqEii m,r qutq ERr (a) qkd 1ii (ii) (b) ssnn ac ifq gqsiqwF*I, itrTT trqrq-fi emf eltt sqq *. dq fr-d{ur qi qvrii * rnq qfd-frk rfrsr +-Bqqtr tt 13 * taq qrn rsifuq qroVrs* *t errqrqo-or *if t etfr t z lP.T.O. (a) Describe a simple experiment (or activity) to show that the polarity of emf induced in a coil is always such that it tends to produce a current which opposes the change of magnetic flux that produces it. (b) The current flowing through an inductor of self inductance increasing. Plot a graph showing the variation of (D (ii) (iii) L is continuously Magnetic flux versus the current Induced emf versus dl/dt Magnetic potential energy stored versus the current. OR (a) Draw a schematic sketch of an ac generator describing its basic elements. State briefly its working principle. Show (D (ii) a plct of variation of Magnetic flux and Alternating emf versus time generated by a loop of wire rotating in a magnetic field. (b) 30. (a) Why is choke coil needed in the use of fluorescent tubes with ac mains p-n {Rr E-{i if Hfqfud qf#ureit sr {iqtq it sdq drfqq qt{ {s*i $ se t (b) eneq?rs'qfrqE sTti-cif +1 vorqnr t qnieq tr ffi (D err;Rfers Er+s arrern s1frqflq.6ru1 elT sr ffiur ts,q rsREtdr =ro (ii) ii rq erFrflqrtrdt ql Fq t r p-n riRr + frq q{qfqkrs Er+q it v-r qfiTflq{frmfl*-q n-sryrqil t*qqrfr Rq-*-{q ? Bqdq fu-s u-onflmqr "rar t t t r qer.IT (a) ffi <rks{ + tr{ wdt + dq w*'qrrs sfu qrq-sq *- snqr {r futfi *1fuq (b) ffi qtks{ et fu's ron erqkd m.rh fuq sr{E{r ii mrqr qrdr t ? r (c) sllErars'qfrqq sTnq *i q6rzrdr t qrh ftifrq t+' Cp frqrq { *tt n-p-n <ifqs{, t*u r+nffi eg qr r*tq Fra{ft + -dr q,r q-qf{ *-rf,r t r ac erm dFr +frq{d tdfuq sslllt I t4 (a) State briefly the processes involved in the formation of p-n junction explaining clearly how the depletion region is formed. (b) Using the necessary circuit diagrams, show how the p-n junction are obtained in (i) characteristics of a Forward biasing (iD V-I Reverse biasing How are these characteristics made use of in rectification ? OR (a) Differentiate between three segments of a transistor on the basis of their size and level of doping. (b) How is a transistor biased to be in active state ? (c) With the help of necessary circuit diagram, describe briefly how n-p-n transistor in CE configuration amplifies a small sinusoidal input expression for the ac current gain. 55tyr l5 voltage. Write the

Formatting page ...

Top Contributors
to this ResPaper
(answers/comments)

luckykaul
(19)

SH0ckWaV3
(1)

Gayathri Gangad...
(1)

Vanshi Gupta
(1)

Formatting page ...

Additional Info : CBSE Class XII Board Solved Question Paper 2014 Physics
Tags : CBSE Board 2015, Specimen Question Paper 2014 Physics, Science, solved sample mock guess question paper, cbse class XII syllabus, cbse class 12 previous years model papers, cbse, cbse papers, cbse sample papers, cbse books, portal for cbse india, cbse question bank, central board of secondary education, cbse question papers with answers, cbse model test papers, solved board question papers of cbse last year, previous years solved question papers, free online cbse solved question paper, cbse syllabus, india cbse board sample questions papers, last 10 years cbse papers, cbse question papers 2014, cbse guess sample questions papers, cbse important questions, specimen / mock papers 2015., cbse, cbse papers, cbse sample papers, cbse books, portal for cbse india, cbse question bank, central board of secondary education, cbse question papers with answers, prelims preliminary exams, pre board exam papers, cbse model test papers, solved board question papers of cbse last year, previous years solved question papers, free online cbse solved question paper, cbse syllabus, india cbse board sample questions papers, last 10 years cbse papers, cbse question papers 2017, cbse guess sample questions papers, cbse important questions, specimen / mock papers 2018.

cbse12 chat

Horizontal lines at:
Guest Horizontal lines at:
AutoRM Data:
Box geometries: