TNclass12PHY

7/29/2019 TNclass12PHY

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MODEL QUESTION PAPER

Higher Secondary Second Year Physics

Tim e : 3 hrs . Mark : 1 5 0

PART I

Not e : (i ) An s w er a l l t h e ques t ions . 3 0 x 1 = 3 0

(i i ) Choose a nd w r i t e t he cor rec t a nsw er .

(i i i ) Each ques t ion ca r r ies one m ark .

1. A dipole is p laced in a u niform elect r ic fie ld with it s a xis pa ral le l to the fie ld .It experiences

(a ) on ly a n et force (b) on ly a torqu e

(c) b ot h a n et for ce a n d tor qu e (d ) n eit h er a n et for ce n ot a t or qu e

2 . Th e u n it of p er m it t ivit y is(a) NC2m 2 (b) Hm 1

(c) C2N1m 2 (d) Nm 2C2

3. The nu mber of lines of force tha t rad ia te ou twards from one cou lomb cha rgeis

(a) 1.13 10 11 (b) 8.85 10 11

(c) 9 10 9 (d) infinite

4 . On moving a cha rge of 20 C by 2 cm, 2 J o f work is done, t hen t h e pot en t ia ldifference between the points is

(a ) 0 .5 V (b) 0 .1 V

(c) 8 V (d ) 2 V

5 . In t h e ca se of in su la t or s , a s t he t empera t u re dec rea ses , r es is t ivit y

(a ) in crea ses (b) decrea s es

(c) becom es zero (d) rem a in s con ta n t

6 . In a t angen t ga lvanome t er , for a cons t an t cu r ren t , t he deflect ion is 30o. Theplane of the coil is rotated through 90o. Now, for the same current , thedeflection will be

(a) 0 o (b) 30 o

(c) 60 o (d) 90 o

7 . In a t h e rmocoup l e, the t empera t u re of t he cold jun c tion is 20oC, thetemperature of inversion is 520oC. The neutral temperature is

(a) 500 oC (b) 540 oC

(c) 270 oC (d) 510 oC


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8 . E lect r om a gn e tic in d u c t ion is n ot u s e d in

(a ) t ran s form er (b) room h ea ter

(c) AC gen era tor (d) ch oke coil

9 . Which of the fo llowing devices does no t a l low d .c. to pass th rough?

(a ) res is tor (b ) ca pa citor

(c) in du ctor (d ) a ll th e a bove

10 . The un it hen ry can a lso be wr it t en a s

(a) VA1s (b ) s

(c) wb A1 (d) all

11 . In a n AC circu i t , t he cu r ren t I = Io s in (t / 2 ) la gs beh in d th e em f

e = E o s in (t + / 2 ) by

(a ) 0 (b) / 4

(c) / 2 (d)

12. In an e lect roma gnet ic wave, the ph as e difference between elect r ic fie ld a ndmagnetic field is

(a ) 0 (b) / 4

(c) / 2 (d)

13. Of th e following, which one is a biaxial crysta l?

(a ) tou rm a lin e (b) ice

(d ) ca lcit e (d ) m ica

14. If th e wavelength of th e light i s reduced to ha lf, then th e amou nt ofscattering will

(a ) in crea se by 16 t im es (b) decrea s e by 16 t im es

(c) in crea se by 256 t im es (d ) decrea se by 256 t im es

15 . A Nicol p r ism is ba sed on th e pr inc ip le of

(a ) refra ct ion (b) reflect ion

(c) dou b le refra ct ion (d) d iffract ion

16. The ra t io of radi i of the firs t th ree Bhor orbits i s

(a ) 1 : 2 : 3 (b) 1 :1

2:1

3

(c) 1 : 8 : 27 (d) 1 : 4 : 9


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17. In h ydrogen at om, which of the following t ran si t ions pr oduce a sp eetra l lineof maximum frequency?

(a) 2 1 (b ) 6 2

(c) 4 3 (d ) 5 2

18. In Millikan s experim ent , an oil drop of ma ss 4 .9 10-14 kg is ba lan cedby applying a potential difference of 2 kV between the two plates which are2 mm apart . The charge of the drop is

(a) 1.96 10 1 8 C (b) 1 .602 10 19 C

(c) 12 C (d) 4 .9 10 19 C

19. If th e potent ia l difference between th e cathode an d th e target of coolidgetube is 1 .24 10 5V, then the minimum wavelength of cont inuous xraysis

(a ) 10 (b) 1(c) 0 .1 (d ) 0 .01

20. The ph otoelect r ic effect can b e explained on the ba sis of

(a ) corpu scu la r th eory (b) wa ve th eory

(c) elect rom a gn et ic th eory (d ) qu a n tu m th ery

21 . The wavelength of the m at te r wave is independent o f

(a ) m a ss (b) velocity

(c) m om en tu m (d) ch a rge

22 . The t ime taken by the rad ioact ive element to redu ce to 1 / e t imes i s

(a ) h a lf life (b ) m ean life

(c) h a lf life/ 2 (d) twice th e m ean life

23 . The ion i sa t ion power is ma ximu m for

(a ) n eu t ron s (b ) a lph a pa r t icles

(c) gam m a ra ys (d) beta pa r t icles24 . Wh en 5B

10 i s bombarded wi th neut ron and part icle is emitted, theres idual nucleus is

(a) 3Li7 (b) 1H

2

(c) 1H3 (d) 2He

4

25 . In a nu c lea r reac t or cadmi um rods a re u sed t o

(a ) speed u p n eu t ron s (b ) s low down n eu t ron s

(c) a bsorb n eu t ron s (d) rem ove h ea t


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26. In a Colpi t t s oscilla tor c ircui t

(a ) ca pa cit ive feed ba ck is u s ed (b ) t ap ped coil is u s ed

(c) n o t u n ed LC cir cu it is u s ed (d ) n o ca pa cit or is u s ed

2 7 . An e xa m p le of ntype semiconductor is

(a ) pu re germ an iu m (b) pu re s ilicon

(c ) s ilicon doped wit h ph osphorus (d ) ge rman ium doped wit h boron

28. Wha t will be the inpu t of A an d B for the Boolean experess ion(A + B ) . (A . B) = 1?

(a ) 0 , 1 (b ) 1 , 0

(c) 0 , 0 (d ) 1 , 1

29 . In T.V. t ransm iss ion , the p ic ture should no t be scan ned du r ing the retu rn

jou rn ey of th e s ca n n in g. Th is is don e by(a ) b lan kin g pu ls e (b) s aw tooth poten t ia l

(c ) hor izonta l synchronis ing pu lse (d) ver t ica l synchronis ing pu l se

30 . Through which mode of p ropaga t ion , the rad io waves can be sen t from oneplace to another

(a ) Grou n d wa ve prop aga tion (b) Sk y wa ve prop aga tion

(c) Spa ce wave p ropa ga t ion (d) All th e above

PART II

No t e : (i ) An s w er a ny 1 5 ques t ions . 1 5 x 3 = 4 5

31 . S ta te cou lombs l aw in e lect ros ta t ic s .

32 . Why is i t s a fe r to be in s ide a ca r than s t and ing under a t r ee du r ing ligh tn ing?

33 . What a r e the advan tages of s econdary cells ?

34 . The r es is t ance of a n ich rome wire a t 0 oC is 10 . If its temperature coefficient

of res is tance is 0 .004/oC, find its resistance at boiling point of water.

35 . What is ca lled su perconduc t ivity?

36 . Define ; ampere in t e rms o f fo rce.

37 . Wha t h appen s to th e value of cur ren t in RLC ser ies c ircu i t , if freqency of the

source is increased?

38. If the ra te of chan ge of cur ren t of 2 As 1 induces an emf of 10 mV in a solenoid,

what is the self inductance of the solenoid?

3 9 . Wh y d oe s t h e s k y a p p ea r b lu e in c o lou r ?

40 . The r e fr ac t ive index of the med ium is 3. Calculate the angle of refraction if

the unpolarised l ight is incident on i t at the polar is ing angle.


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4 1 . S t a te t h e p os t u la t es o f B oh r a t o m m o d el.

42 . In Braggs sp ect rometer , the g lan cing an gle for fir s t o rder spect rum was

observed to be 8 o. Calculate the crystal lattice spacing, if the wavelength of

the xray is 0.7849.

43. Ment ion a ny threee appl ica t ions of photo e lec t r ic cells .44 . Wh at is decay? Give an example.

4 5. Defin e: Cu r ie

46 . Draw the b lock d iag ram o f an oscilla to r and m en t ion the componen t s .

47. The gain of th e am plifier is 100 . If 5% of th e ou tpu t voltage is fedba ck int o the

input through a negative feed back network, f ind out the voltage gain af ter

feedback .

4 8 . Me n t ion t h e a d va n t a ge s of IC S.

49 . Define the inpu t impedance of a t r ans i s tor in CE mode.

5 0 . Wh a t is m e a n t b y s k ip d is t a n ce ?

Part III

Not e : (i ) An s w er t h e ques t ion 6 0 com p uls or i ly . 7 x 5 = 35

(i i ) Of the r em ain ing 1 1 ques t ions , a nsw er any s ix ques t ions .

(i i i ) Draw d ia gram s w herever neces sa ry

51. The p la tes of a para lle l p la te capacitor have an area of 90 cm2 each and a re

separated by 2.5 mm. The capacitor is charged by connecting i t into a 400 V

supply. How much electrostat ic energy is s tored by the capacitor .

52 . Obta in th e cond it ion for br idge balance in Wheats tones br idge .

53 . Expla in the method to compare the emfs of two cells u s ing potent iometer .

54 . A c ircu lar coil o f 50 tu rns a nd ra d ius 25 cm ca r r ies a cur ren t of 6A. It issuspended in a uniform magnetic f ield of induction 10 3 T. The normal to the

plane of the coil makes an angle of 60 o with the field. Calculate torque of the

coil.

55 . Exp la in th e va r ious ene rgy los ses in a t r ans former .

56 . Der ive the exp res s ion fo r the r ad ius o f the n th dark r ing .

57 . Exp la in th e spect r a l s e r ie s of hyd rogen a tom.

58 . Ob ta in E ins te in s ph o to e lect r ic equa t ion .59 . Es tab lish E ins te in s m ass -energy equ iva lence, E = mc 2 .


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60. Calcula te the b inding energy an d b inding energy per nu cleon of 20 Ca40 nuc leus .

Given , mass of 1 pro ton = 1 .007825 amu; mass of 1 neutron = 1 .008665 amu;

mass o f 20Ca40 nuc leus = 39 .96259 amu .

O r

Calculate the mass of coal in ton required to produce the same energy asthat produced by the fission of 1 kg of U 235 . Given : Heat of combustion of

coal = 33.6 10 6 J / kg ; 1 ton = 1000 k g ; En ergy per fiss ion of

U235 = 200 MeV ; Avagadro number = 6.023 10 23 .

61 . Draw the frequency response curve of s ingle s tage CE ampl ifier and d iscus s

the resu l ts .

62 . Draw the fu nct iona l b lock d iagram of AM radio t ran sm it ter .

PART IV

No t e : (i ) An s w er a ny 4 ques t ions in d e t a i l . 4 x 1 0 = 4 0

(i i ) Draw d ia gram s w herever neces sa ry

63. Wha t is an electr ic dipole? Derive an express ion for the electr ic field du e to

an electric dipole at a point on its axial line.

64 . Discus s th e mot ion of a cha rged par t icle in a u niform ma gnet ic fie ld .

65 . Discus s with th eory, the method of indu cing emf in a coil by cha nging it s

orientation with respect to the direction of the magnetic field.

66 . Wha t is kn own as in ter ference? Der ive an express ion for ban dwidth of

interference fringes in youngs double slit experiment.

67 . With the h elp of energy level d iagram expla in th e working of HeNe laser.

68 . Desc r ibe Ba inb r idge ma ss spec t romete r to dete rmine the iso top ic mas ses o f

n u c l e i .

69 . Wha t i s known as rec t ifica t ion? Expla in th e br idge rec t ifier .

70 . With th e help of b lock d iagram , expla in the m onochrome TV receiver .

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TNclass12PHY