R Prerna wer, Rad N, Cnracrs Area, Bsupur, Jamshedpur 83, el (657)89, www.prernaclasses.cm JEE MAN 3 PAR A PHYSCS. A unfrm cylnder f lengh and mass M havng crss secnal area A s suspended, wh s lengh vercal, frm a fxed pn by a massless sprng, such ha s half submerged n a lqud f densy σ a equlbrum psn. he exensn x f he sprng when s n equlbrum s : Mg Mg A σ Mg A σ Mg A σ () + k k M k M k M (Here k s sprng cnsan). kx = Mg σ (A / ) g 7 Aprl 3. A meallc rd f lengh l s ed a srng f lengh l and made rae wh angular speed ω n a hrznal able wh ne end f he srng fex. f here s a vercal magnec feld B n he regn, he e.m.f. nduced acrss he ends f he rd s : (Bωl / ) () (3Bωl / ) (4Bωl / ) (5Bωl / ) 3 l. ε nd = B ( ω ) l 5 x dx = B ω l. 3. hs quesn has Saemen and Saemen. f he fur chce gven afer he Saemens, chse he ne ha bes descrbes he w Saemens. Saemen : A pn parcle f mass m mvng wh speed v clldes wh sanary pn parcle f mass M. f he maxmum energy lss pssble s gven as f [(/) mv ] hen f = [m / (M + m)]. Saemen : Maxmum energy lss ccurs when he parcles ge suck geher as a resul f he cllsn. Saemen s rue, Saemen s rue, Saemen s a crrec explanan f Saemen. () Saemen s rue, Saemen s rue, Saemen s a n a crrec explanan f Saemen. Saemen s rue, Saemen s false. Saemen s false, Saemen rue. 3. K.E ss Max when e = (perfecly nelasc) K.E ss = ( / ) µ rel = ( / ) [mm / (M + m)] JEE MAN 3 (7 Apr 3) Quesn & Sluns www. prernaclasses.cm
4. e [ ] dene he dmensnal frmula f he permvy f vacuum. f M = mass, = engh, = me and A = elecrc curren, hen: [ ] = [M 3 A] () [ ] = [M 3 4 A ] [ ] = [M 4 A ] [ ] = [M A] 4. () [ ] = M 3 Q = [M 3 4 A ] 5. A prjecle s gven an nal velcy f ( ˆ + j ˆ ) m/s, where ˆ s alng he grund and j ˆ s alng he vercal. f g = ms, he equan f s rajecry s : y = x 5x () y = x 5x 4y = x 5x 4y = x 5x 5. () y = u y. ( / ) g where = x / u x 6. he amplude f a damped scllar decreases.9 mes s rgnal magnude n 5s. n anher s wll decrease α mes s rgnal magnude, where α equals :.7 ().8.79.6 6..9 A = A e (C) (5) α A = A e C(5) α = (.9) (.9) =.79 7. w capacrs C and C are charged and respecvely. s fund ha by cnnecng hem geher he penal n each ne can be made zer. hen : (A) 5C = 3C () 3C = 5C 3C + 5C = 9C = 4C 7. () C C = 8. A snmeer wre f lengh.5 m s made f seel. he ensn n prduces an elasc sran f %. Wha s he fundamenal frequency f seel f densy and elascy f seel are 7.7 3 kg / m 3 and. Nm respecvely? 88.5 Hz () 78. Hz.5 Hz 77 Hz 8. () f = [ ( / µ) / ] = [ {( / ) (Y / ρ)} / ] 78. Hz 9. A crcular lp f radus.3 cm les parallel a much bgger crcular lp f radus cm. he cenre f he small lp s n he axs f he bgger lp. he dsance beween her cenres s 5 cm. f a curren f. A flws hrugh he smaller lp, hen flux lnked wh begger lp s : 9. weber () 6 weber 3.3 weber 6.6 9 weber µ R φ =. 9. ( R + x ) π R 3/ where R = cm R =.3 cm and x = 5 cm. Dameer f a plan cnvex lens s 6 cm and hckness a he cenre s 3 mm. f speed f lgh n maeral f lens s 8 ms, he fcal lengh f he lens s : 5 cm () cm 3 cm cm. R = 9 + (R.3) R = 5.5 [(.5 / ) + ( / )] = [(.5 ) / R] ( / ) + (.5 / (.3)) = [(.5) / ] = 3 cm. (herefre fcal lengh = 3 cm) JEE MAN 3 (7 Apr 3) Quesn & Sluns www. prernaclasses.cm
. Wha s he mnmum energy requred launch a saelle f mass m frm he surface f a plane f mass M and radus R n a crcular rb a an alude f R? (5GmM / 6R) () (GmM / 3R) (GmM / R) (GmM / 3R). [ GMm / R] + E = [ GMm / 6R]. A dde deecr s used deec an amplude mdulaed wave f 6% mdulan by usng a cndenser f capacy 5 pc farad n parallel wh a lad ressance kl hm. Fnd he maxmum mdulaed frequency whch culd be deeced by..6 MHz ().6 khz 5.3 MHz 5.3 khz. () f = [ / (πrc)] ( +.6) =.6 khz 3. A beam f unplarsed lgh f nensy s passed hrugh a plard A and hen hrugh anher plard B whch s rened s ha s prncpal plane makes an angle f 45 relave ha f A. he nensy f he emergen lgh s : () / / 4 / 8 3. = ( / ) frm A, = ( / ) cs 45 = / 4 4. he supply vlage a rm s. he ressance f he lead wres s 6 Ω. A 6 W bulb s already swched n. Wha s he decrease f vlage acrss he bulb, when a 4 W heaer s swched n n parallel he bulb? Zer l ().9 l 3.3 l.4 l 4. = [( / 46) 4], = [( / 54) 48] =.4 5. he p v dagram represens he hermdynamc cycle f an engne, perang wh an deal mnamc gas. he amun f hea, exraced frm he surce n sngle cycle s : P P P v v v p v () (3 / )p v (/) p v 4p v 5. () Q = 5P + (3 / ) P = (3 / ) P (nly psve Hea s aken) 6. A hp f radus r and mass m rang wh an anglular velcy ω s placed n a rugh hrznal surface. he nal velcy f he cenre f he hp s zer. Wha wll be he velcy f he cenre f he hp when ceases slp? (rω / 4) () (rω / 3) (rω / ) (rω ) 6. CAM: mr ω = m (v ' / r) r + mv '. r = v ' = ω r / JEE MAN 3 (7 Apr 3) Quesn & Sluns 3 www. prernaclasses.cm
7. An deal gas enclsed n a vercal cylndrcal cnaner supprs a freely mvng psn f mass M. he psn and he cylnder have equal crss secnal area A. When he psn s n equlbrum, he vlume f he gas s and s pressure s P. he psn s slghly dsplaced frm he equlbrum psn and released. Assumng ha he sysem s cmpleely slaed frm s surrundng, he psn execues a smple harmnc mn wh frequency : A γ P M π () MP π A γ π A γ M P π M A γ P 7. Mehd :Check dmensnally Mehd : (dp / d) = γ.(p / ) (Adabac) dp = γ(p / ). Adx f resrng = dpa = ((γp / )A ). dx ω SHM = [γp A / M] / 8. f a pece f meal s heaed emperaure θ and hen allwed cl n a rm whch s a emperaure θ, he graph beween he emperaure f he meal and me wll be clses : () θ θ θ 8. θ = θ + (θ' θ ) e K 9. hs quesn has Saemen and Saemen. f he fur chces gven afer he Saemens, chse he ne ha bes descrbes he w Saemens. Saemen : Hgher he range, greaer s he ressance f ammeer. Saemen : ncrease he range f ammeer, addnal shun needs be used acrss. Saemen s rue, Saemen s rue, Saemen s a crrec explanan f Saemen. () Saemen s rue, Saemen s rue, Saemen s a n a crrec explanan f Saemen. Saemen s rue, Saemen s false. Saemen s false, Saemen rue. 9. Shun ressr need be nrduced n parallel ncrease he range. hus ressance f ammeer reduces wh ncrease n range. JEE MAN 3 (7 Apr 3) Quesn & Sluns 4 www. prernaclasses.cm
. n an CR crcu as shwn belw bh swches are pen nally. Nw swch S s clsed, S kep pen. (q s charge n he capacr and = RC s Capacve me cnsan). Whch f he fllwng saemen s crrec? R C S S Wrk dne by he baery s half f he energy dsspaed n he ressr () A = τ, q = C / A = τ, q = C ( e ) A = τ /, q = C ( e ). q = C ( e / τ ) when τ = CR. w cheren pn surces S and S are separaed by a small dsance d as shwn. he frnges baned n he screen wll be: S d S D Screen Pns () Sragh nes Sem Crcles Cncenrc Crcles. Pah dfference a all pn n he screen a equal dsance frm cenre f screen reman same.. he magnec feld n a ravellng elecrmagnec wave has a peak value f n. he peak value f elecrc feld srengh s : 3 / m () 6 / m 9 / m / m. () E = cb = 3 8 9 = 6 m. JEE MAN 3 (7 Apr 3) Quesn & Sluns 5 www. prernaclasses.cm
3. he ande vlage f a phcell s kep fxed. he wavelengh f he lgh fallng n he cahde s gradually changed. he plae curren f he phcell vares as fllws: () 3. f s ncreased, wll decrease and afer he hreshld value wll becme zer. 4. he characersc f an ED s : R Y G B () B G Y R R Y G B 4. 5. Assume ha a drp f lqud evapraes by decrease n s surface energy, s ha s emperaure remans unchanged. Wha shuld be he mnmum radus f he drp fr hs be pssble? he surface ensn s, densy f lqud s ρ and s s laen hea f vaprzan. ρ / () ( / ρ) / ρ / ρ 5. (du / d) = (dq / d) [d(. 4πr ) / d] = [d(4/3)πr 3 ρ ) / d] r = ( / ρ) JEE MAN 3 (7 Apr 3) Quesn & Sluns 6 www. prernaclasses.cm
6. n a hydrgen lke am elecrn makes ransn frm an energy level wh quanum number n anher wh quanum number (n ). f n >>, he frequency f radan emed s prprnal : ( / n) () ( / n ) (/ n 3/ ) ( / n 3 ) 6. f [{ / (n ) } ( / n )] f ( / n 3 ) (Q n >> ) 7. he graph beween angle f devan () and angle f ncdence() fr a rangular prsm s represened by: () 7. 8. w charges, each equal q, are kep a x = a and x = a n he x axs. A parcle f mass m and charge q = (q / ) s placed a he rgn. f charge q s gven a small dsplacemen (y << a) alng he y axs, he ne frce acng n he parcle s prprnal : y () y ( / y) ( / y) 8. F = (q / 4πε ) [y / (a + y ) 3/ ] (q y / 4πε a 3 ) (Q y << a) 9. w shr bar magnes f lengh cm each have magnec mmens. Am and. Am respecvely. hey are placed n a hrznal able parallel each her wh her N ples pnng wards he Suh. hey have a cmmn magnec equar and are separaed by a dsance f. cm. he value f he resulan hrznal magnec nducn a he md pn f he lne jnng her cenres s clse (Hrcnal cmpnen f earh s magnec nducn s 3.6 5 Wb / m ) 3.6 5 Wb / m ().56 4 Wb / m 3.5 4 Wb / m 5.8 4 Wb / m 9. () B = (µ / 4πd 3 ) (m + m ) + B h =.56 4 Wb / m 3. A charge Q s unfrmly dsrbued ver a lng rd AB f lengh as shwn n he fgure. he elecrc penal a he pn lyng a a dsance frm he end A s : A B (Q / 8πε ) () (3Q / 4πε ) (Q / 4πε ln) (Q ln / 4πε ) dx 3. v = (Q / 4πε ) + x = (Q ln / 4πε ) JEE MAN 3 (7 Apr 3) Quesn & Sluns 7 www. prernaclasses.cm