Formatting page ...
"APl~R - , -.,._ ,)klr.~z,:- (Tl-1 EORY) . (Maximum Marks : 70) (__ ; '' V~ (Time allowed : Three llours) J -\ ~ (Candidates ore allowed additional 15 minutes for only reading the popcr The)1must NOT start writing during this time .) SECTION-A Question l . (A) Choose the correct alte rnative (,,), (b), (c) or (d) for each of the questions g iven be low . (i) (ii) (iii) (iv) (v) ~rus : A soap bubble is given a nega tive c harge . Then its (a) decreases (b) (c) r<"rnains un ch ,,nged (d) none of the abov t: increases The capacitance of a capacitor does not depend upon : (a) size of the plates (b) shape of the plates (c) separation between the plates (df charge on the plates lf a diamagnetic so lution is p o ured into a U- tube and one a rm of this U-tube is placed between the poles of a s trong magne t w ith the 11"teniscu s in a line wi th the field 1 then the level of the solution w ill : (a) n sc (c) remain same } b1't1II (d) oscillate slowly It is possible to observe total internal reflec tion w hen light travels from.. : (a) g lass to water (b) air to glass (c) air to watt' r (d) water to glass The s tt1 i lity of a nucleus is decided by its : (a) number of proton s (b) number of nucleons (c) b indin g energy per nucleon (d) binding energy (B) Answe r the following questions briefly and to the point : (i) H ow does the magnetic permeability differ for dia-, para- and ferronla gnetic ma te rials? (ii) Find magnetic flu x density t1t a point on the axis of a long solenoid hav in~ w h en it is carrying a current of 2 A. ml.s/rn -- , .__ -!?:, (iii) Wha t is m eanloy 111ne-c~ns tant of an L-R circuit ? (iv) Write two applications of internet.. (v) Two lenses of fo cal le ng ths 5 cm and 50 cm a re to b e used for m aking a telescope. Which lens will you use for the objective ? (vi) What is Brewster angle for w a te r ? The re fr ac tive index of water with res pect to a ir is NJ 1.33. (vii) A s;herica l' mirror is he ld under wa te r. Will its foca l len g th change ? SECTION-B Question 2. An electric dipole con sistin g of cha rges 2 ~tC each separated by 0.01 rn ,12.irt is ~..,laced in a uniform e lectric fie ld of in ten s ity 3 x HJ-1 NC- 1 Calculate th~ to119ul' ,1et 111 3 uplln il w hen it is inclined to th e lin es of force at an ang le of 45 . '-, :-.:ct " - - - - t"(:--- . . I ' , I ' l J'- :-_ I I f' ~ ~-'-. ~ vY\ 1-> , Question 3. .~ '. , , l - . Although the drift velocity of electrons is ve ry small, yet an electric bulb lights up almost instantly wlwn switched on, w hateve r be the distance of the bulb from the switch. Wh y ? \ .Question 4. A certain mono_chroma~ic light travelling in air is i~ent on a glass p la te al the polarising c1ngle. Angle of refraction in g lass is found to be 32". Cnlculate : (i) the polaris ing c1ngle, (ii) refractive index of t lass. ...... , -, . i /I... V ' ur''\. l "1 Question 5. ' 1.. :.., 1. 1 ~ , . r y-1 ~ , A given __wi re is bent into a rectangu lar loop of size 15 cm x 5 cm a n d p laced (a) I /f. perpendicular to a m agnetic field of 1.0 T. Within 0.5 second, the loop is changed into a 10 cm square and the fie ld increases to 1.4 T. Compute lhe,1, e.m.f. induced in the coil. , ;, OR When the current flowing through a coil P decreases from 50 A to 0 in 0.2 second, .in (b) e.m .f. of 60 V is ind uced ac ross tl1e terminals of an adj ace nt coi l Q. Calcu la t~ the ' f coefficient of rn~-tual inductance of the two -coils P and Q. Question 6. - - - - -- , \\;\ ,..- ~ t \ ~ ~ ~ J.,<i} ,' 1 i I ., Figure below shows a block diagram of a transmitter. identify the boxes X and Y an d state their fu nction s : YTransrri!tinu Message 1v7~---"l)[ylf..._ _J_, L'..J J' Signal Question 7. C'\ , f: ', - Figure alongside shows a point P near a long conducto r _XY carrvino a current i. MN is n short current-ca rr ying , 0 . ' . conductor, kept at the point P, parallel lo the cond ucto1 XY. (i) What is the direction of magnetic flu x de nsity ' B' at the point P due to the current flowing through XY ? (ii) What is the direction of the force experienced by the - - conducto r MN due to the current flowi ng through XY? v _), ' Antenna >~ ~ t b:-.1 1i; ~ (1' \ 1-- ry l~-( , , ' M 1y;.,..,,& 0 , ,_1....i..,J-: / i' I N! ~ ~ /J -,Y / ' "\AAl4>\At Question 8. , . . A 50 F capacitor, a 30 n resistor and a 0.7 H inductor are conne,c ted in senes to an a.c. ' e' ocriven bye = 300 sin (200 t) volt. C.1lculate pe.:ik supp I y w I11 c J1 generates . c " an emf 1 value of the current flowin g through the circuit. <' Question 9. (a) (bl Find the momentum of the photon of ene rgy ~:_O eV . OR l Calculate the momentum of a photon of green ligh t of 11. = 332 nm. Ques ti on 10. Light of wavelength 4500 A in _ . __ vacu um enters into a glass block L)f r,,fr,1ct1vc mdex 1.:-i . What is the wavelength of light in the g lass block ? 0 1,1 / w. . , ,/ Q uestion n. ( ) Sctee, Figu r e a lo n gsidl' s h ow~ the p os itions of the first ;i;:lS. bright fringes i t n i(!)~ on eilher side_ o f th e centra l l brii'ht fringe O in Youn g ' s double s lit expe rime n t. 'J, -'" 1 mm M S: Mis the mid-point of S1, S2 Cornp l'.1lc the wavelen g th of lig ht. -. 1<-D~im ->\ Question 12. Why are the NANO a nd NOR logic gates call1;d d igi tal building blocks 7 - - Question 13. The activity of a radioactive material drops to 1 /16th of its initial va lue in _24 hours Calculate its h alf-life and the decay cons tant. Question 14. (a) Calculate th e s teady curre nt lh rough thd 2 n resistor in the circu it s h own in Lh<: 'j figure. 2n , 1 f, - -1 .\ ; - - ~ , A B 3n ~ n\ 2 F OR . i Fig ure below shows a uniform m ,m ganin wire XY o f length 100 cm a nd resistan&:;9 0 ,) connected to an acc umula tor D of e.m .f. 4 V ;:incl inte rnal resis ta n ce 1 ~ n through a variable resis tance R. E is a cell of e .m .f. 1.8 V connected to the wire XY via a jockey J and a central zero galva nomete r G. It is found that th e glavanome ter s h ows no deflection when XJ = 80 cm . Find the value of R . / - M- 1 D j_ ~ / 0 lh_. 1 X 0cm 80cm - - -- - ~ - -__. y J 100 cm 1-. u-~ >, ' .- Questio n 15. Explain the u se of a wave rectifier. p - 11 junction diode as a rectifier. Dra w th e circuit diZ'lgr;rn, uf ;, ful l Q uestion 16. (a) A p la n o-conve)IJ'le n s hc1s radius ol cu rv,,turt' 10 c m . l ls f<x ,d lens th 1s oll ( 111 undc:r \\Jkr Calculate the rdra ct1\-L' index nf thl' m,1 tcrial of the lens, given 1e'..rc1Ct 1\ o.. mdl.:'\ vf \\"dkr I ~= } OR (b) A con vex lens o f focal leng th 5 cm is to be used as a sim p le microscope. Where sh o uld :rn o bject be kep t so t hat the im age fo rmed by th e lens lies a t the lec1s t d 1st,111ce D o f distinct \'lsion (D = '.25 cm ) ? Also calcul ate th e m agn ifyin g powe r of this instrument 111 this set u p . Question 17. \V1 th proper labelling o f the axes, d raw the input a nd o utp ut ch mactens ti c curve::; of 17-1 1 tra nsistor in commo n emitter con fig ura tion. 11- Question 18. (i) Na me a series o f lines of hydrogen s p ec trum which lies in : (1) vis ible region (2) ultraviolet reg ion. (i i) Write Bohr' s fo rmula to calculate wavelen g th (),.) of visib le light, emi tted by h ydrogen, an d exp lain the mean in g o f each and eve ry sy mbol used . Question 19. Drav,1 a labe lled diagram o f a nuclea r reac tor, sta tin g the function of each p ar t. SECTION-D Question 20. ( ;: 1 nh t.- in "1 expression fo r the t1eld ~tren:~th, c!t_a1':)'._Poin t on (i ) axial iine (ii) equato rial line of an electric d ipole. OR (b) State Kirchhoff s law fo r th e an alysis of an elect ri cal networ k .rnd apply it to ob tain the condi tion for a balan ced Wheatston e b ridge. (c.. , w\.M..J-- ,'.1 Q~estion 21 . ~ v ~ .)-I-" ""-.CT~J .....s\ . .I.A~ 0 R . f .J ~ c._G1L'--~ ~ Show that 1ll both _c harging a n d d 1sch a rg1n_g of a ca p ac itor thro ugh a resistan ce, the ~un;ent s!c1rts with its m ax i!1, um value and talls off exp on entially .~.Jv\\~--"-1 r.>~1)1 I~ ~ (b) 0-uf_ d _.A.-lj iJ- ~ ~c.o pe ~ '2>w--~ 1h 4 t'i --':J::;i e.,i I /-\ ch arged capacitor is con n ec ted ac ross a n in d uctor. Sh ow tha t the di s::l tctrge of the ca p ac ito r is oscillntor y. Obtain an expression for the frequency of oscillation s. Question 22. (a) (i) W ith the help of a l;ibe lled diagram, sh ow that frin ge sep aration f3 s lit exp eri m en t is given by AD 0 = d , w here 111 Young's doub le the terms h ave their u s ual meani.ngs. (ii) O bt a in the rat io o f th e in te rfe rence fr i n ge w idt hs ~ , a n d ~ ~ obtain ed ., ith mon och romatic re d lig ht of 11. 1 = 660 n m and ultraviolet ligh t of ic~ "" J30 nm . OR (b) (i) Obtc1i n tht? rel c1 tion c s in 0 = ). fo r tlw fi rs t minimum of the d iffraction p.itlem '-)f ,, ~m~le slit of wid th 'e' u sin g light of wavelen g th 'A.'. (ii) In Fra tmhofer's s ingle: slit d iffracti on experi 1nent, h ow d oes sc m1-<rns 11J:i r width t!:e <::~~r,:d brigh t- fringe J cpen~ =in s lil w 1dtl~ c' 7 o_,J l~ ,)\ ~ v.
|
