THI LÝ L3-2011(ĐÀO DUY TỪ-HN)

Trudng TF{PT E€'thi thr} dai hoc ldn 3 (ngdy 091a112011) Dbo Duy Tri tr Ha Mdn: VAt li' khdi A Ngi (Thdi gian ldm bdi: 90 phitt, khdng kd thdi gian phdt ill) Ma d6 thi: 301 Ciu I' MOt con ldc ld xo dao ddng didu hoi, trong qu6 trinn aoo Aong vAt ludn chiu t6c dupg cria 1-rc k6o vd c6 bidu thdc F = - 3cos(5rct - n/3XN), vAt ndng c6 khdi lu'ong n =2O0g.liy g = l0m/s2, n2 = lo.Bi€n d0 dao d6ng crja vAt lh: A, 6crn B. 3cm C.l2cm D. Bcm C0.u 2- Con ldc don c6 chidu dii I = 0,64m, vdt ndng c6 khdi lu'ong rn = 1009, dao dong di€u hoi & 'oi c6 gia tdc trong trudrrg g = l0 (rnls2), rc2 = I0. Lfc t = 0, cou lac qua vi trf cdn biing v) dang chuydn d6ng theo chidu du'ong cria quy dao v6i vdn tdc 1On(crn/s). Sau 0,2s, ddng ndng cfra con lic bing: A.5,5.104J B.2,5.1OrJ c. 3,5.10 rJ D.0,15.10'J CAu 3. Hai ngudn phdt s6ng co tai hai didrn A vi B cirng. tdn sd, cing bi0n d6, cilng pha ndm sau rrong mdr bd nu'6c. X6t hai didm: didm M nim ngo)i du'bng thing AB v) didrn N ndrn tGn doan thing nn c6 hi€u khoin!'c6ch r6i A vi B bang rndt sd bdn nguy€n ldn bu6c s6ng, coi bi€n dd s6ng kh6ng ddi. Chon d6p 6ir dring A. Phdn trinu6c ivM dao dOng, &N dfing ydn. B. Phdn tft nu6c &N dao dong, oM dfrrg y6n. C. C6c phAntftnudc 6M vi &N d€u dfng y€n. D. C6c phdn tri'nu6cdMvn &N ddu daJd'61g. CAu 4. Doan mach xoay chidu AB rnic ndi tidp theo thri tu gdm rndt di€n trcy thuCn R = 30O, mor tu di€1 c6 di€n dung bidn Adi vi m6t cudn dAy khdng thudn cirn c6 116 tu ciirn L. Di€n np E 2 dAu mach c6 'bidu thric ld: u = 120 J2 cosl00nt (V). M li didm ndi gilfa di6n tr& vh tu diOn. Khi tu di€n c6 di€n dung C = U03l4n)F th) dien 6p hi0u dung hai ddu doan rnach MB dat gi6 tri nh6 nhdt l) ljva = 60 V. Khi d6 di€n 6p hi€u dung hai ddu cuOn dAy bf,ng A.6oJzv B.9o v c. loo v D. too "fl v CAu 5. Trong [?ch dao d6ng di€n td' li tudrg, bidu thfrc cria dbng di6n tror-rg mach li i = Scosot (rnA). Trong rlibi gian ls c6 5.10s ldn d616lr cira cudng dO dbng di0n dat ctrc dai. Khi cu'dng ao a;ng di6n rrong mach bing 4mA thi di€n tich cfra tu di€n bing: A. 23,9.10.?C 8.477,5prC c.0,95.10ec D. 1,9lnC CAu 6. MOt tia s6ng d6 c6 tAr-r sd f = 4,2.l0toHz chidu til chdn kh6ng v)o m6r loai thuy tinh c6 chidt sudt tt = 1,52 ddi vdi tia s6ng d6. Van tdc cria hrrh sdug ttong chAn khOng li 3.108m/s. Budc s6ng cria 6ph szing d6 & tr€ir trorrg thuy tinh li: 4.0,47 ptn B. 0,54pun C. 0,66pm D. l,O9prn Clu 7. Mdt nguyOn tft hay phAn tri'c5 thd ph6t ra bao nhi6u loai luong trt ning luong? A. Mdt loai . B. Hai lo.i. c. Ba lozri. D. Nhidu loai. C1u 8, M6t dng Rorighen ph6t ra tia^X c5 budc s6ng nh6 rrhdt li 0,5 nm. L.{y hang sd Pling h = 6,625.10-3aJs: viip rdc ilrrth siing trong chAn khOng c = 3.108rn/s. Ndu ting hi€u di€n th€ giira andt vi cat6t th6m SkV thi tia X phdt ra c6 tdn sd l6n nh0t bang: A. 8,15.Ia1'Hz B. 2,53.10rsH2 C. 5,24.10r8H2 D. 0,95. lTteHz Cliu 9. Chon ddp hn dfng vd s6ng dr)rrg tr6r-r m6t dAy din h6i: A. Nhfrrrg didm tr6n dAy dao ddng cing pha v6i nhau thi c6ch nhau nrdt sd nguy€n ldn btr6c s6ng. B. Nhirng.didm tr0n dity rrfun trong khoing giua hai bung kd tidp thi dao ddng cing pna. C. Hai didm pung c6ch uhau mOt sd 16 lAn nfr:r bu6c s6ng thi clio dong ngug" phal ^ D. Nhfrrrg didrn tr€n d{iy chch uhau m6t rndt phdn tu bu'6c s6ng th) aao aOng nguo. " pha v6i nhau. CAu 10, MOt vat thuc hi€n ddng thdi hai dao ddng didu hoi. cing phuong, ciurg tdn sd t' = 5 Hz, c6 gia tdc cuc dai bing 10^6 Inls2. Bien d0 dao ddng thrl nhdt l) I crn, dO l6ch pha cia hai dao ddng li nl3. L{y nz = 10. Biel cl6 cira dao dOng thf hai bing A. I cur CALI ll. M6t ngudn s6ng co O c6 phuotrg tr-inh: u = 4cos(100rut)(rnm) truydu doc theo tluc Ox v6i tdc d6 2Ornls ; trong d6 t lA thdi gian du-o. c tinh biurg giay(s). Li dd cfra didm c6 toa d0 x = 25 rn sau 0,2s kd til khi ngudp bit ddu dao dOng bfurg: A.2Jimn 8.0 C ZJimm D 4mm Ciu 12. Didu niio sau dAy l) sai khi n6i vd ddng co kh6ng ddng b6 ba pha? A. DOng co kh6ng ddng bd ba pha bidn diOn niurg thinh co ning. B. Ddng co khdng ddng b0 ba pha hoat dOng dua tr€n nguy6n tic hoat ddng cria ddng co kh6ng ddng b6. C. Ddng co khdng ddng bd ba pha sri'dung til tru'bng quay cfra narn cham vinh ciru. D. Trong ddng co khdng ddng b6 ba pha tdc dO quay cfra rOto lu6n rrh6 hon t& clQ quay cfia tD'trubng. B. 2 crn C. 3 crn D. 4 crn \ / Mr,1 t> ,-' l, ,tzv, /l'-r^-r'c4,-_ I CAu 13. Mach dao d6ng c6 thd bidr] ddi trong giii tdn sd ti' l0 MHz ddn 160 MHz bdng c6ch thay ddi khoing ct'rch gifa hai bin tu didi pli&ng. V6i giAi tdn n)y thi khoing c6ch gifia c6c bin tu thay ddi A. 4 ldn B. l6ldn C. 160 ldn D. 256lArr CAu 14. Trong thi nghi€m giao thoa 6nh si{ng cfra YAng, khoAng c6ch giiizr 2 khe sdng l) 2mm, khoAng cich ti'2 khe ddl rnin Ii lrn. Khi chiOu s6ng khe F 6nh s6ng dotr sic dorr sic c6 bu6c s6ng l"' thi khoing vdn do duo.c bdng 0,2rnm, khi chi€u sdng khe F 6nh s6ng dorr s6c c6 bu6c s6ng L, > X, thi tai vAn s6ng bAc ba cua {r"rh siing c6 bu6c s6ng ),, c6 vAn sSng cfra 6nh sdng c6 budc s6ng l-r. Bu6c s6ng 1", bang: A.0,45pm 8. O,Strun C.0,6pm D.0,64prt Cdu 15. Tropg dao d6ng didu hoi cfia con l6c don, s6 dao ddng tl-ruc hiOn drrqc trong 1 giiry s6 A. tang,-khi con16! chuydn dOng nhanh ddn dt)u di l€n theo phu'ong thing dfnrg. B. gi6rn, khi con lic chuydn d0ng chflm ddn ddu theo phuorrg ngang. C. g-iim, k|i cor-r lic ctruydn dQng cham ddn dtju di xuong theo phuong thing dfurg. D. talng, khi con lhc chuydn ddng ddu theo phuong ngang. CAu i6. Mdt doan mach gdm m6t dien tr& R, indt cu6n cAm thudn v) mot tu di€n mic ndi tidp. Di€n 6p dAt vho hai diiu doan mach c6 bidu thuc: u = U Jicos2nft(V), tiin sO f thay ddi clu-o. c. Khi tdn so f = fr thi dung khdng blng 500, cArn kh6lg bang 200O. Khi f = fz= 4oHzthi di€n rip hi€u dung hai ddu di0n tro R dat gi6 tri cuc dai. tdn sd f, bang A.\OHI B.40Hz C' 60Hz D- 80Hz Ciu 17. Khi s6ng Arn truydn trong m6t mdi trudr-rg thi: A. Bi6n d0 s6ng tai rnOt didrn phu thu0c vio tdn sd s6rrg. B. T6c dd s6ng truydn s6rlg phu thu0c vio tdn sd s6ng. C. Bu6c s6ng khdng phu thuOc vlo tdn sd s6ng. D. Chu ki s6r-rg v) tdc dO truydn s6ng ti l€ nghich v6i nhau- CAu 18. Mdt con lic ld xo dao ddng didu l-ro) c6 khdi lu'ong m Ldy n2 = 10. Tdc dd trung binh cfra vAt trong mOt chu ki bing: A. 40 cm/s 8.45 crn/s C. 50 cm/s - 2009, co nf,ng cira cor-r iac W = 0,04J. D. 60 cm/s CAu 19. Mdt duong day tii dien c6 di6n tr6 tdng c6ng lh 100, cdng sudt ndi truyen di l) 40 kW, cOng sudt hao phi rr€ndAyld2560W,he-sdcongsudtcriamachbing 1.DdgiimcdngsuAthaophitrendaychicbn257ohao phiban diu thi cliOn 6p hi€u dung noi truydn diphii ting thOrn bao nhi6u? Ctu 25. Su ph6t s6ng cfrar vAt niro du6i dfly khdng phii l) su plr6t quang? A, Con dorn d6m. B. Ddn LED. C. B6ng dbn dng. D. Hd quang' A. 4000 v B, 2500 V c. 2000 v D. 1500 V Cdu 20. Chon ddp 5n sai vd s6ng dien til: A. Mot di€n tich didm dao ddng didu hoh bLic xa ra s6ug diOn tit. B. Tai m6r didrn bAt ki tr€n phuong truydn s6ng, vectd cu'bng dd diOn tru'brrg E vh vecto ciirn ri'ng tl' F adu Uidn thiOn tudn hohn vi vudng pha vdi nhau. C. S6ng di€n tit c6 mang theo niurg lucrrtg. D. Khi s6ng di€n til truydn tir chAn kh6ng viro mdi tru'dng thi buoc s6ng giim. C1u 21. Trong nguyen ti'hidr6, c6c qui dao ding K, L, M, N c6 ndng luong tuong ri'ng 1I Er = -13,6eV, Er= -3,4eV, n, = -i,S"V, EN = -0,84eV. Lt'y hirng sd Plang h = 6,625.10-3'Js; vAu tdc 6nh sdug trong chAn khdng " "= g. ib*,r/r. Kiii nguycn ttr' ciiuydn til trang ifrai aU-tg c6 ndng luong E* vd trang thdi co brin thi vach quaug phd c6 tdn sd l6n nhdt thuOi ving nh)n thdy do nguyOn ttr c6 thd phdt ra bang: A.3,08.10rsH2 - B 2,9.10r'Az c.6,l8.l0r4Hz D.2,tl8.10r4Hz Ci1u 22. M6t con 16c lb xo c6 d0 cfng k, vat niurg c6 khdi luo. ng m thi chu kl dao d6ng didu ho)r li T. Cit ld xo k\rn hai phdl bipg phau rdi gh6p song song v6i nhau vir treo v0t c6 khdi luong m' tl-ri chu ki dao ddng vAn li T. Kdt luAn nlo sau day li dring? A. tni = 2m. B. n' =m12. C. m'= 4m. D' rn' = tn/4 C.lu 23. Khi chieu tia si'urg phric t4p gdrn hai thinh phAn vdng vi chim ti'troug urr6c chdch rn6t g6c t6i mIt phiin cfch gifra nu6c vi khOng khi thi A. goc hqp b&i tia khfrc xa rnhu vhng v)r rnf,t phAn cdch l6n horr g& hSp b&i tia khfrc xa rniu chi\m vI miit phAn c{ch- B. g6c khfrc xit cira tia mi\g chl6 nh6 hol g6c khric xa crta tia miu vhng. C. cfuc g6c khric x4 cria tia rniu chi\m v) cila tia tnhu ving nh6 horr g6c t6i. D. tia khr.ic xa li tia sfirg cilng rniu vdi tia tdi. CM 24. M6t cor-r l6c lb ^otit tign m6t n-r[t s]ur nilm ngarg. Ld xo c6 d0 citrg k = 25 NAn, khdi luong cria vdt m = 50 gou.,, trg sd ma s6t gifia vdt vi rrdt sln li 0,02. Ldy g= 10 rnls2. Dua vit ddn vi tri ld xo n6n B crn r-di budng nhe, vdt dao iOng tiiddn chtrn Joc theo truc lE xo. Sd chu ki mh vat thue hiOn du'oc cldn khi dirng hin bnng A.40 8.50 c.80 D. 100 Cttt 26' Diy dln hdi AB c6 ddu B cd dinh, ddu A clao ddng didu hoi v6i bi€n d6 6rnrn, rr€n diy c6 s6'g dii:rg. Tai didm tr€n dAy c6ch rndr bung bane llt2lbn bu6c s6ng thi aai aong "Jl frie,, AOll*g,'""' A.3.,6rnni B.6{imm C.6JJmm D.6mm Cdu 27 - Didu nio sau day li sai khi n6i vd nguyOn tic hoat.ddng cria c6c loai m6y phdt di€n xoay chidu? A. Nguy€n tic hoat dOng cfra m6y phrit dien.xoay chidu ldlua tr€n hier-r tuoni c{rn tnrg dien tn. B- Khi tD thdng qua not vbng ddy bidn thi€n ddu thi trong vbng dayxudt hidn moisudt dieridong cirn drrg xoay chid'. C- Khi cho cdc vdng day quay trong til'trudrrg cd dinh thi ;6 rhd rao ra suat di€n d6ng xoa| chidu. o '"'r ' D' Khi cho til'tr-udng quay, cdc vbng day cd dinh thi c6 thd tao r-a sudr di6n ddng xoa! "hi6u. 9ll zs Trong rndt mOi trudng c6 s6ng trn. truydn di vdi tdc d0 u = :4omlr."rdn .rd am ndrn rrong khoing 350H2 < f < 450H2. Khoing crich gifia hai didm tien cing phuotrg iruydn am dao d6ng pguo.c pha vdi nhau lI 2nr. Khozing cdch gAn nhau nhdt trOn cing phuoqg truydn c6 dao hong am vuong pha v6i nhau b[lg: A. 1 m 8.0,4 m C. 0,2jm D.0,2 m Cdu29. Dat vio hai ddu doan rnach mdt dign 6p xoay chidu: uou = IJocos(l00nt + xl6) (V). Tropg khoing thdi gian ti'0,003s ddn 0,00tls kd'tD'thbi didin ban adu, aien 6p gifra hai ddu doan mach clar gid tri u = -tJo/2 vfro thdi didrn: A. 0,004s B. 0,005s C. 0,006s D. 0,007s CAu 30. Trong mach dao ddng didn ti', n6u tiurg sd vdng dAy cfia cuon crirn thi : A. Tdn s6 dao d6ng cria rnach tdng. B . TAn sd dao d6ng c&a rnach giirn. C. Tdn sd dao dd.ng cfra rnach khdng ddi. _ D Kh6ng ttrd ket ludn vd srr thay ddicfra tdn sd clao d6. ng. CAu 3l:.Mqt m6y bidn 6ph4 6p c6 ti sd vdng day_cuon so ct'p v) thrl cdp lh 10. Cu6n so cdp rnic vio lgudn di€' xoay chidu c6 hiOu diOn thd hi0u dung U = 1 BOV. il6 quu dien tid thuAn cria cudn so .ef, aien ir & thuri' cta cud' rhrl cdp li r = l,5f). Hai ddu cudn thf cdp ndi v6i mot di6n rrd thudn R = 6f:. Cu'dng do hieu dung cfra cid'g di€n tro'g cudn thit ciip bang: A. l,8A B.2A C.2,4A D.2,8A Ciu32- Ding einh sdng^mit trdi chidu vlo cdc loai vAt lieu sau: tdrn 96, chat bdn aau, "ie,-r gach, ti'm kirn lorii. Hi€n tuong quang di6n c6 thd xiy ra 6 _ A. mQt loai vdt li6u. B. hai loai vat lieu. C. ba loai var lieu. D. bdn loai vat li€u. CAu 33. Trong thf nghiem giao rhoa dnh .sdng cfra Y ang, khoing "a}r gi", z khe s6ngffi;#,;;'illlng c6cli til 2 klre d0rr min l) 1,8rn. chidu s6'g ddng thdi hai bdc xa do'sfc c6 bu6c s6ng ?", = O,l4lrm v)r 1", = 0,7zpm Itong kholrng rdng L = 2an tr€n milt, rnr chinh gifra li vArr sdng trung tam, sd viu sirng ",i,i hai br-icxa kh6ng c6 miu gidng miu cfra vAn trung tArn biurg: 4.20 8.23 c.2s D. 30 cA' 34. Bi€r phdq ni.o sau day kh6ng g6p phdn rirng rri€u sut'r cfra rn6y bien irp: A. Dr)ng l5i sit c6 di€n rr& suit nh6. B. Dilng dAy c6 diQn rro sudt nh6 lim dAy qut'n m6y bien 6p . C. Ddng l6i s6t gdm nhidu ld sdr m6ng gh6p cich dlen vdi irhau. D. Dit cdc lh sirt cfra l,5i sit song song v6i mirt phirng chri.a c6c dudng sfc ti Cxu 35. Mdt dao ddng didu hoi, vxt di qua vi tri can bang vdi vdn tdc lorc(cmls). Khi vAp rdc cira vdr c6 d6 l6n li sn Ji (cmls) thi gia tdc cria n6 c6 dd l6n li I (rnls2 ). L{y n2 = 10. Chu ki dao d6ng cria v1r biurg: A. 0,12-5s B. 0,25s C. 0,5s D. ls CAu 36. Chon dhp t'ur sai trong cdc cXu san: 4 C1o chdt quarg dAIr, khi c6 hnh sdng thich hop chidu vi\o rh) dd1di€p tdt. B' Mudn gny dud.9 hi6n tu'ong quang di6n trong thi 6nh sdng kicir thfch phii c6 bu6c s6ng nh6 hcnr gi6i 1ia' quang dAn crizr chdt quang d6r-r. q G-i6i hau quang dan cua cdc chit quang din uh6 hon gi6i han quang di6n cria c6c kirn loai. D Quang di€n trd vi pin quang di€n hoat ddng du'a trerihien tLrclrg quang di€p tropg. CAU 37' Mot doarr mach gdm nrot di€n trdR m.{c noi tldp v6i rnot "uoir "rim."oii vr\o hii ddu doan rnach rn6t di6' dp xoiryclridu:u=lJtficos(l00nt)V,khicl6di€n 6ptfrcthdihai dducudnciml€chphaT5osc.rdridi€.6ptfic thdi hai dAu didn tro. C.':rc di€n 6p hiOu dung hai ddu rli€n tr& R vi hai ddu cu6n ciirn ldr-r luot li -sO rD V vri 100V. H0 sd c6ng sr"rlit crla rnach bing D. 112 A.0,965 s. ,lt n c. Jin N, ,/ n-/ n f, c - Vn-rt 4'-(L fl >l CAu 38. Trong thi nghi€rn vd giao thoa s6ng trOn mit nu6c, hai ngudn kdt hop A vi B dao d6ng ctng pha v6i tAn s6 5OHz. Didm M nltn trOn doan AB c6ch trung didm O cria AB li\ 3crn, ihuoc van cuc rid;thll i. fO" Oo CAu 39. Mach dao d6ng gdm cuOn dAy c6 dO tu cim L, tu diOn c6 di€n dung C vi di6n tro thudn R. Io vi\ I li gi6 tLi cuc dai vd gi6 tri hi6u dung cria cubng d0 dbng di€n trong mach, Uo vi U lI gi6 tri cuc dai vi girir rri hi€u dung cria . hi6u di€n thd hai bAn tu. Tirn d6p 5n sai vd cOng thrlc tfnh c6ng suat toi nhiOt tror-rg rnach: A. P= CRU'z/L B. P= LRUO2I(}C). C. P= RIO2/2 D. P = RC'U2ro2 CAu 40. Khi lfir luot chidu 6nh sdng don sic c6 bu6c s6ng 0,2pLm vi 0,25pLrn vio rndt mdt tAm kirn loai thi €lectron quang di€n c6 c6c ddng udng ban ddu cuc dai hon k6m nhau 1,5 ldn. Gi6i han quang di€n cfra kim loai la\ A.0,5 pun 8.0,33 pLn C.0,14 pLm D.0,11 prm CAu 41. Mdt vAt dao dOng didu hoi vdi bi6n dq A = 10 crn. Tai thdi didm t = 0 v4t c6li d6 lir 6 crn vi dang di theo chi€u du'orrg cfra truc Ox. Quing dudrg vAt di du-d. c trong thdi gian ll4 chu ki kd tD' t = 0 birng A. 6 cnl B.8cm C. 10 cm D. 14 crn Cdu 42. Chon dip 6n sai vd thuydt luong trt iinh siing A. ClrDrn iinh siing lh clrirn cdc phOtOn . B. M6i phdtOn mang ndng luoug x6c dinh e = hf (f h t6'n sd cria s6ng 6nh sdng don s6c tuong frrg) C. C6c ph6t6n bay v6i tdc dd c = 3.108 rnls doc theo tia s6ng. D. M6i l{ln rnQt nguyOn tfr'hay phdn tir' ph6t xa hay hap thu 6nh s6ng thi chring ph6t ra hay hap thu ph6t6n. Cltu 43. Khi truydn thdrlg qua v0 tinh, tdn sd cfra s6ng thuOc diip dn nho? A.2,5.105H2 B.3,5.l03KHz C.42,5.104 kHz D.4.1014H2 Cdu 44. Dirt vlo hai ddu doan mach ndi tidp gdrn rn6t bidn tr& R, mdt cuOn cirn thuAn c6 cim khiing ld Zrvit m6t tu di€n c6 dung khdng Z" mQt diOn 6p xoay chidu c6 di€n 6p hi€u dung U. Khi thay dtii gi6 tri cria bidn trcr R blng R, vI bing R, thi cOng sudt ti€u thu diOn cfra doan mzrch ddu bang P; khi R = Ro thi cdng sudt ti€u thu dien cfra doan mach dat cuc d+i P*"^. Bidu thric niLo sau diy li sai? A. RrR2 = (ZL-Z)z B. R'+ Rz = U2lP C. Ro = JR& D. RlR2 = f]tpn,"* CAu 45. MOt ngudr-r s6ng co c6 phu'ong trinh uo = 6cos20nt(cm), t6c dd truydn s6ng lh 80cm/s. Tai thdi didrn t li d6 . s6ng tai A l) 3cm vi vAn tdc dao ddng c6 d0 lm dang tdng, khi d6 rnOt phAn t& s6ng tai B cdch A lb 2crn c6 li d6 A.3."6crn B. -3 J3 crn c.3 ",,11 cm D. 4 Ji ctn Ciu 46. MOt doa^n mach xoay chidu gdm rndt cudn dAy kh6ng thuAn cim vi rndt tr-r di6n C, hi6u diOn the hai ddu cu6n diy l0ch pha 900 so v6i hi0u di€n the hai ddu doan rnach. Ndu giim diOn dung cira tu di€n thi hi€u di€n thd hieu dung hai ddu cudn dAy thay ddi the nio? truydn s5ng tr0n rnit nu6c lh: A. 30crn/s B. 60crn/s A. Tf,ng. C. Ban ddu tf,ng, sau d6 giim. A. di6n 5p cfra tu di6n biurg khdng. C. di€n tich crla mdt bin tu di€n dat cuc dai. A.u" - 100\tD cos(lOOrut + nl6)Y C.u. - 100J3 cos(l00nt + nl3)Y C. 90cm/s D. l2Ocmls B. Giirn. D. Ban ddu giim, sau d6 ting. B. di€n 6p cira tu di6n dat cuc dai. D. plra ban ddu cria dbng di€nld rc12. B. u" = 200\fzcos(100rut + nl4)Y D. u" = 200cos(100nt + 2nl3)Y Cdu41. Corll6cdondaod6ngtainoic5g= l0rn/s2vdibi€ndOg6cnh6liO,lrad.Khiquavirr-icdnbirng,c6vAn tdc 50cm/s. Chidu dii dAy treo bing A.2m B.2,5rn C. 1,5m D, 1rn Cdu 48. MOt mach dao d6ng di€n ti'tu do LC, khi cu'drg d6 dbng di€n trong mach dat cuc dai th) Ciu 49. Mdt doan rnach AB gdm mOt cu6n dliy vi rn6t tu di€n rnic ndi tiep. Dat vz\o hai ddu doan rnach m6t di€n dp xoay chidu uas = 100"l2cos(100nt + nlL)Y thi di€n irp gilra hai ddu cuon .lAy c6 bidu thrhc n = 1 00 J- sin( I 00n t + 4nl3)Y . Bidu thfrc di6n iry gifr'a hai biin tu di6n li CAu 50. Chon d6p 6n sai vd quang phd phdt xa A. Quang phd cria 6.nh s6ng do c6c chat rin, l6ng, khi khi bi ntrng n6ng d&r nhi€t dO cao ph/rr ra li\ quang phd phiit xa cria chring. B. Quang phd phft x4 gtirn quang phd Ien tuc v) qlrang phd vach. C. Quang phd vach do chAt khi 6 dp sudt thlip phdt ra, khi bi kich thich bdng nhiet hay bing dien. D. Quang phd tien tuc li dii rniu li€n tuc til d6 ddr.r tfin & moi nhi6t dd. I{UONG nAro cIAr pi rHr rHr}lAn 3 (ngiy }stlttzlrr) Ma dd 301 CAu 1. Dd crilg k = mor2 = 0,2.(5n)2 = 50N/m. Lrrc k6o vd F = -kx+ - 3cos(5nt x = 0,06cos(5nt - n/3) m -+ A = 6cm -+ Chon A Cdu 2. tdn sd g5c or = ,[g I t = Jlu 0,64 = m/0,8 (radls). T4i t = 0 var & didm N 11€n vbng rrdn Siru0,2s g6c quay o, = crlt =rrl4 , vt &M c6li d6 xr= AlJi -+ v = u".n*f J2= l}n/Ji cm/s -+ D0ng rrdng Wo = n/12 = 0,1.( O,h/Ji f p=2,5.10iJ-> Chon B CAu 3. S6ng cotruy€n trong nudc ld s6ng dgc *+ phuotrg dao d6ng tring v6i phuong truydl s6ng *+ tr€' dudng 'di hai ngudn thi hai s5ng c6 cing phuong dao ddng -+ N thoi rnln didu ki0rr s6ng kdt hoD, cdn didrn M, hai s6ng til hai ngudn truydn ddn c5 phuotrg dao ddng AM vi BM khdc nhal elz[ Ar r sB N *+. kh6ng thoA rndn didu ki€n s6ng kdt hop n€n khdng c6 giao thoa tai M -+ N c6 hi€u khoing cichtli A v) B beurg rndt sd b6n nguy€n lAr-r budc s6ng -+ N dao d6ng v6i bi€p dQ cgc tidu, n6 drirrg y€n cdn M thi dao d6ng + Chon A Cau 4. C6 thd d€ ding chrirrg minh khi di€n dung C thay ddi rn} Un, dat gi6 td nh6 nhdt thi mfihi6iqng hudng *> Zt=Zc= 40f); {Jru= I."*r= 60V, ln}I,,,"* =U/(R +r)-+ 6Ah= n0K30 + 0+ r = 30O -+ tdpg trdcriacu6n day t 2,,,= .rl r' + Z; = 50f); I,,,"* = U/(R + r) = 12916A =2A,+ Di€n 6p hi€u dung hai ddu cu6p dAy {J"a = I,."* Z"o = 2.50 = 100 V-+ Chon C Cliu 5. KhoAng thdi gian gifa hai ldn cu'dtrg d6 dbng diOn c6 dd ldn dat cuc dai li l/2 chu ki -> 5.l}sTl}= ls -) chu ki dbng di€n li T = 4.10'6s -+ o) = 2rcff = 5.lOsrc(rad/s) -+ di0n tich crc dai crja tu clien go = Ilco = 5.10r/(5.10'n) = 1O€/?r(C). 6p dung cOng thr.'rc (i[J' + (q/qJ'= 1; thay i= 4mA,t = 5rnA, go = 10 8/n(C) - q = 1,91(pC) -> Cthon D. Cdu 6. Budc s6ng cfra 6nh sdng d6 trong chAn khOng Lo = clf = 3.1031(4,2.1014) = 0,714.10{m *> Bu6c s6ng cria dnh slmg d6 trong thuf rinh l" = }"oln = A,714.10611,52 = 0,47(pm) -+ Chon A Cdu 7 - Nguy€n til hay phAn tri c6 thd phr{t ra nhidu loai phdton tric I) c6 thd ph6t ra nhidu loai luong rfi' nirng lu_o. ng -+ Chon D. CAuS.Tac6hc/}".,in=eUer(1); ht,,"-=e(Uer<+8000) (2).L{y(2)-(l)=hf.,"^-ltc/",,,,,,=8000e.Thayh,cvif,n,i,, I f,,"* = 2,53.1018H2 -) Chon B. Cdu 9. Khi c6 s6ng dirng tr€n mdt dAy din hdi - Nhflrrg didrn tr0n dAy nirn gifra hai nLit kd tidp dao ddng cing pha v6i nhau-+ A sai vz\ B sai - Nhirng didm tr'6n dAy narn & hai b€n cfra rn6t nfrt thi dao d6ng ngudc pha v6i nhau-+ D sai. - Hai didm bung cdch nhau )"12: 3Xl2; 5)"121 lttic 1) crich nhau mOt sd 16 ldn nria bu6c s61g t6) dao d6pg rgrr y. c pha-+ Chon C. Cdu 10. Tac6 a,,,", = cD2A *) A = a',",/cD'= tOr,5/(tOru)'=0,01 n6,r = 1/J.,n. Lai c6 A, = A,t+Ar2 + 2A,Arcosq; thayA= "u5",r,Ar = lcrn, e=nl3taduocAz= lcm+Cho1 A. Cdu I 1. Sau thdi gian 0,2s th) s6ng truydn tii'ngudn di du'oc rn6t quing du'dng s = vt = 20.0,2= 4rn; t+i didrn c6 toa d0 x = 25m s6ng chua truydn ddn, didnr n)y v5r-r dritrg yOn chua dao d6ng -+ li d6 dao d6ng uu = 0 -) Chon B. Cdu 12. DOng cd khdng ddng b6 ba pha st dung tit trLldtrg quay cfra ddng di€n xoay chi€u ba pl-ra chfr k60'g sri dung tt trudng cria nam chArn vJnh criu -> C sai -+ Chon C. CAu 13. Tdrr s6 cria rnach dao dOng f = ll{ZnJ LC )+ f thay cldi 16 llin thi C phii thay ddi 162 = Z56lAn-+ khoii'g cltch gifra hai bin tu phang thay ddi 256 lAn -+ Chorr D. CAu14.Tac6i, =XtDla)1", =i1 afD=0,2.10r.2.10-3ll=0,4(!Lrn).Theobi\ira3i, =krir_>31", =kr)"r_> )"r=3X1k2= 1,2lkr(pn'r); lai c6l, > l, -+ 1,21k2> 0,4 -> k, < 3 -) k, = l;Z-V6i kz = 1 -+ )"r= l,Z(pyrt): loai vi tlrudc vilug hdng r"rgoai; vdi k, = 2 -+ ),r= 0,6(Lim) -> Chop C. Cdu 1.5. Ttong dao ddng ditiu hoi cila con l6c don, sd dao dQng tirirc hion cluo.c trong I giay li tdn so dao d6'g. Khi con l6c chuydn ddng nhanh din ddu cli l€n theo phuong thing dfrrg thi gia tdc tiong tru'Ong bidu kidn g'= g * a > g -) chu ki T' < T -+ f' > f -+ tAn sd dao d6ng ting -> Chon A. - khi con lirc chuydn ddng chtrn ddn ddu theo phuong ngang rhi g' - ^l s' * a' > g-+ f' > f *+ B sai. - khi con lfc chuydn ddng chAm ddn dtiu di xr-rdng theo phuong tlrfrng dfrrg gidng nhu con l6c chuydr-r d6ng nhanh dAn ddu di l€n theo phuong thing dd'ng -+ f tiurg -+ C sai. V.(,p1";- - khi con lac chuydn d6ng ddu theo phuong ngang thi tdn sd dao ddng khdng ddi bang tdn s6 dao dong khi con l5c treo 6 rnot vi tri nhAt dinh -> D sai. CAu 16. Tac67-=2nftL = 200f); Zc= 1l(2nf rC) = 50fl ->Z'2.= LlC 10000 (i). Khi f =fz= 40Hz thi di6n dp lrai ddu R datcuc dai -+ mach c6 c6ng huong ) fr=40H2= UQIILC ) (2). Til(1) vn Q) -+ C = 103/(8lr)F-) f t = ll(ZrcZcC) = 80(Hz) -+ Chon D. CAu 17. Khi s6ng Am truydn trong mdt rndi tnrhrg thi phAn trl vAt chAt m6i trudng dao ddng cu'6ng bLic v6i tdn sd brlng tdn sd cfra ngudn vi bi€n dO dao d6ng cu'&rg bric nly phu thudc tdn sd dao ddng cita ngudn -+ Chon A. - Tdc dQ s6ng truydn chi phu thuOc bin chdt mOi tru'bug rni khdng phu thu6c v)o tdn sd s6ng -+ B sai. - Bu6c s6ng l" = vlf -+ l" phu thu6c v)o tdn sd s6ng + C sai. - Chu ki s6ng vi tdc d6 truydr-r s6ng trong mOt mdi tru'dng li kh6ng ddi -+ D sai. Cxu 18. Co ning cira vat W = mo:2A2l2 -+ aA = JzW l* -+ ZaAIT = JZW I ^. Tdc dQ trung binh v,r, = 4Aff - z^7Zw l,u /x=2Jr.0,04,t01 /n=0,4(m/s) = 40crn/s -+ Chor-r A. CAu 19. C6ng sua't hao phf tr€n dudng day AP = P'RAJt (l)-+ U'z = p'RAp = 400002.1012560 _+ U = 2500V. Khi congsudthaophichicbnbangAP'=257oLP-+257oLP=P'R/(U')'(2).Tac6(l): (2)=4 =(U'/U)2 -+IJ'N=2-t IJ' =2U =2.2500 = 5000V -; fJ'-U = 5000- 2500 = 2500V -+ Chon B. CAu 20. Tai rnot rtidm bit ki tr6n phuung truydn s6ng, vectd cu'bng d6 di6n trudng E vi vecto cirn frrg tt E ddu bidn thiOn tudn hoin vi ciurg pha v6i r-rhau chri'khdng phii vu6ng pha + B sai-+ Chon B. Ca'u 21. Khi nguy€n tri'chuydn til trang th6i dung c6 nlng luong En vd trang th6i co bin thi vdi su chuydn mfc udug luong til'E* vd E, s6 cho vach quang phd c6 tdn sd l6n nhdt thu6c ving nhln thdy -+ hf = E" - E,- -) f = (EN - EL)/h = [- 0,84 - (- 3,4)]1,6.10le16,625.10-3a = 6,18.10r4H2-+ Chon C. Cdu 22. MOt lb xo c6 d6 crlng li k, khi crit l)rn 2 phdn bing nhau th) do cring cria rndi nila bing 2k, sau d6 gh6p clrfrrg song sor-Ig v6i nhau thi dO cdrrg cfra lb xo m6i bing 4k. Ban ddu chu ki dao dOng f = 2n J nr/ k, sau d6 chu ki birrg T =2nJrr14k -+ tn'14= m -+ m'= 4m -+ Chon C. Ciu 23. Xem liinli vd v0 su khfc xa cria tia sdng til'nu6c vilo khdng khi Ta sd c6 kdt ludn g6c hqp bdi tia khfc xa miu ving vh mit phAn cdch l6n 'hon g6c hop b6i tia khdc xa mhu chirn vi rnat phAn ci{ch-+ Chon A. Khdng khf Ving Ciu24. Gii srl ban ddu bi6n d6 dao ddng li A, sau rn6t chu ki biOn dd giirn di Al thi quing dLrdrrg vat di du'oc trong m6t clru ki d6 li s = 4A - ZLl. Co n[ng cria vAt giim di AW =kA2lZ - k(A - Ll)'Z, phdn co nf,ng giim di bidn th)nh c6ng cincrialtrcrnasdtA,,,,=F,,,.s=ftixgs=pLrng(4A -ZLl) + AW =An,,4 kA'12-k(A-Alf/2=pLmg(4A -2L1)-+ kAl(2A-Al)=4prmg(ZA-Al)+Al= pmg/k=4.0,02.0,05.10125=0,0016rn=0,l6cm.SochukirndvltthrchiOn duo.c li n = A/Al = [3/0,16 = 50 -+ Chon B. Ctu25. Anh s6ng hd quang Ii su phdt sdr-rg do c6 su ph6t xa nhi€t €lectron chft kh6ng phii su phdt quang -+ Chon D. Clru 26. Didrn tr€n diy cdch bung sSng Xll} n€n cdch nrit s6ng li ),14 - Xll} = )"16. Bi€n dd dao ddng cfia rndt didm trOn dAy liL A = l}acos(Zndl)" + nlL)l=l2.6cos(7n16 + nlT)l= AJ3 mm -+ Chon C. Ctu21. Khi tn'thor-rg qua rndt vbng dAy bidn thi€n didu hoi thi trong vdng dAy xudt hiOn mdt sudt diOn ddng chrn iirrg xoay chidu cl-rf khdng phii tD'thdng bidn thiOn ddu + B sai+ Chon B. CAu 28. Ta c6 (2k + 1)n = 2ndlL=Zndflv -+ f = (2k+ l)v|26= (2k+ l)34W (2.2) = (2k + 1).85 + 350< (2k + 1).85 <450-+k=Z-+t{insds6ngf=(2k+l).85=475(Hz)*}},.=vlf=3401425=0,8(rn).Khoingcirrchgdnnhaunht't trOn cing phuong truydn c6 dao ddng irn vuOng pha v6i nhau bdng ),,14 = 0,2(m) + Chon D. N Cnu29. Tai t = 0 chdt didrn chuydn ddng trbn dtiu 6 M, khi dien 6p u = -Uo/2 thi chdt didni o didrn N hoirc E. Tai N lir thdi didrn t = T 16 + T I 12 + kT = Tl4 + kT = 0,0214 + 0,02k = 0,005+0,02k(s)-+0,003<0,005+0,02k<0,008-+k=0-+VAytaithdididmt=0,005s tlri n = -IJolZ.Didn E lirn tuong tu khdng tl-roi indn di6u ki€n dAu bii-+ Chon B. Ciu 30. Trong mach dao dOng di€n tt. ndr-r truig sd vdng day cfia cuOn cArn thi dO tu cim L tang -+ tdn sd dao ddng crla rnach f = llQn^[rc : girrrr + Chon B. CArr 31. Vdi miiiy bien zip ha dp ta c6U,l(U, + Irrr) = N,A{z -+ U'/(U, + UrrrlR) = Nr/N, -+ 1[t0/(U, + 1,5U2l6) = l0 -+IJ2+U214=lll-+Ur=14,4Y-+Cudngd0ddngdi0nquadiOntrtvRbangl=UrlR=14,416=2,4Y+ChonC. CAu 32. Hi€n tuong quang di€n chi c6 thd xiy ra & kim loai (quang di6n ngoii) hoic chAt quang dAn (quang di€n trong) -+ xiy ra & chtt b6n d5n vi tdrn kirn loai -+ Chon B. Nu6c cAtr 33. Khoing vAn i, = xlDla= 0,54.106.1,8/0,8.103 = 1,215(rnm), khoing vdl i, = )v2D/a=0,72,106.1,g/0,g.10-3 = 1,62(mn).SdvAnsdngcfra)', lis6kreZthoirndn- 10/1,215<kr <10/l,Zl5-+-g,Z<kr <g,2,+c6lTgidtri cirak, thoimln-)c6 17vensdngcia)"r ,SdvAnsdng crta),"rl)sdk, e Zthoitpfll1- 10/1,62<kr < lO/1,62 +- 6,2 < k2< 6,2 -+ c5 13 gi6 tri cfra k, thoii m6lr -) c6 13 van s6ng cria 1", -+ Tdng sd vAn s6ng cu. hai h€ va' l) 30. Tfrrhsdvdnsfirgtlr)ngnhau crlahai h€vAn: tac6n,l", =flzLz-+O,54nt=0,'IZn2-+ 3 r; ={12_) ltl =4 _+khoilg cdcl-r gifra hai vi tri trirng nhau kd tidp xo = 4it = 4.1,215 = 4,86(rnm) -+ sd vi tri trilg lhau ctra hai vdn siing cria hai bricxalisdk ezthoh6ft1-1014,86<k<10/4,86 >-2,06<k<2,06-+c65giatri"i,ukthoi,na,.,]c65vi tri tring nhau cfrng ld 5 vi trf cirng miu v6i vAn trung tam, ndn c6 10 vln shng cfra hai bric xa nim 6, 5 vi tri 'dy -+ sd vi tri khdng cdng rniu v6i vAn trung tArn le 30 - I0 = 20 -+ Chon A. Cnu 34. - Dir.rg l6i s6t c6 di€n tr'& sudt nh6 khOng Anh hu&ng gi ddn hi€u sudt cfra rnriy bidn dp -+ Chon A. - Dirrg ddy 96 diQn tr&sudt nh6 lim dxy qudir rn6y bien 6p th) didn rr& nh6 n€n hao pi-,i ao toA nhiet ii. - Ding l6i sit.gdm rfiidu ld sit rn6ng gh6p cdch"di€n v6i nhau dd giAm r6c dung nhilt cta ddlg phu-co. - Dit cdc l5 sit cria l5i sit song song v6i mil phang chfra c6c du'dng sric ti'ati talp trung c6c duoTtg sfc tir. Cdu 35. Ta c5 (v/v","*)'+ (u/a","*)'= 7 -+ 1SnJ3 lfin)2 + (100/a,,,"*)2 = l-) (100/a,,,"")2 = l/4 -> a,,,"_ = 200(cm/s2) -> ,4" t9g6c cfra dao ddng 0r = ik"*/vn,"^ =20Oll0rc=Z}/x(radls) -+ chu ki T = \n/a = l(s) -+ Chon D. lau 36 ChAt quang dell :g thd ding.tia hdng ngoai dd tao ra hi€n tu'ong quang di€n troirg, cbn c6c kim loai phii ding 6nh siing nhin thdy (vdi kim loai kidrn) hoac tia tri' ngoai vdi cic kim ioii kh?c, do vAy gi6i han qr-iarrg dai cfra c6c chdt quang dl'16'hon gi6i han qua'g di€n cta c6c kim loai -+ chon c. cdu 37. Theo giin dd vecto thi di€n 6p hi6u dung hai ddu diOn tr& cira cudn cim u, = u.ocos750 = 100( ",16 "5)14 =25 "6 atj - l)v -+ up + U, = 50 ^[t + 25 ^lit .,/J - rl = 25 nE.( ",6 + t)V. Dirrh li him cos ra c6 fJ2=lJo2+U.u'+2URU"dcos750-)U2=(50rli)'*1002+2.50Jt.100cos750=(50nD)t*1002+ 2.50\1ry 100("v6 - ,D)/+ = so' 1./3+ l)2-+ U = 50 (J5+ t) + H€ s6 c6ng sudr cua doan rnzrcl.r cosq - (UR + U,)ru = Ji /Z -+ Chon C. CAu 38. Didm M nim trdn AB vi ci'rch trung didrn O cfra AB l) 3cm -+ hieu drrdrg di cfra hai s6ng tir A vh B dd' M bing6cm.Mthuocvat]cuctiduthfi 3 -+ (2k+ l)Xl4=6cm,v6ili= 2-+5X/4=O -+ )1"=4,gcrn *+rdcd0rruy€n s6ng v = }.f = 4,8.50 - l2(crn/s) -+ Chon D. Cdu 39. Ta c6 CUo2 = LIo' -+ Io' = Cllr'lL. C01g suat toi nhi€t trong rnach p = Rlorl2 -+ C dfpg -Tlray Io2 = CIJo'lL ta du'oc P = RCU',/(2L) = p6gz/ L -+ A dfng - Thoy L = l/(cco'?) J P =RC2U2co2-+ D dfing. B cho bidu thric sai -+ cho' B. C0u40.Tac6hcl\",=A+Wr 0);hclXr=A+Wz(2).Vil, <lr)'W, =1,5Wr-+hcft,",-A+l,5Wr(3).Tn(2)_+ l,Shcl'r= l,5A + 1,5W, (4) -+ (4) - (3) -+ l,Shcl\,'r-hcl)"t = 0,5A = 0,51-rcA.o-> 1,5/)"2- l[.t = l/L6. Thay ),r= 0,25ptm, Lt = 0,2 prn ta duoc l"n= 0,5pLm -+ Chon A. cau 41. Tai t = 0 ch# didm & M tren vbng rrdn (tuong rlng didrn I rr-€n rruc ox), sau 1/4 chu ki chat didrn quay duo. c g6c nlz den N tr€n vdng trdr-r (tu'ong dng didrn J trOn truc ox), vdt di duo. c quiurg du'irng s = IC + cJ. Ta c6 oI = 6crn -+ IC=4crn; OJ=IM =.|rc'-62 =8c1n->CJ= 10-8- 2cn-+s=4+ Z=6crn-+ChonA Cnu 42. c:ic pl-rOt0n bay trong chdn kh6ng v6i t& do 3.l03rn/s + c sai -+chon c. cAu 43. Truydn thdng qua v6 rinh dtrng s6ng cuc ngin c6 tdn sd tir' 102 MHz ddn 425 MHz ndrn trong khoing trOn *) Chon C. 103 MHz. TIin so 42.5.10^ kHz = Cliu 44. Khi thay ddi gi6 tri cfra bidn tr& R biurg R, vr\ bf,ng R, tl-ri c6ng sudt ti€u thu di€p cfra doa' rnach ddu ba'g F ta d0 ding chring rninh du-o.c RlR, = (Zr-2.)2 vift,+ R, =IJ'lP + A vi\ B dfng. Khi R = R0 rl;i corig sudt ti€u rhu iiiOn cfra doan rnach dqt cp dai P,,,.,-+ Rn = JRd, + c dirng. D6p 6n D sai + chon D. CAu 4-5. Tai thdi didm t li dd s6ng ttri A li 3crn v) vAn tdc dao ddng c5 d0 l6n clang ring -+ chdt didrr dang di vd pliia vi tri ccn biing, rr€n vdng trdn li didm M (tren t1.rcli I co li dd 3crn) J ue - 6cos20nt = 3cm -+ z}nt = nl3. Tai didrn B cich A 2ctn c6 phuong trirth uu = 6cos(20rct - Zndl?"), v6i d = 2crn vi X = vlf = 80/10 = Scm -) us = 6cos(20 rct - nl}) = 6cos(nl3 - rc12) = 3 ",6.,n -+ Chol A. CAu 46. Khi hiOu di6n the hai ddu cu6n ddy l€ch pha 900 so v6i hi€u di€p rhd hai ddu doan mach rhi hi€u di€' thd lriOu dnng hai ddu tu di6n C dat cuc dai-+ Z" = (R2 + Zrr)lZr=RrlZ, + ZL ^+ Z.> Zr_+ mach c6 tfnh dulg kh6ng _+ ,) o \'i7 \/M rrrt(p4aJ khi giirn C th\Z.tdng, mach vAn c6 tinh dung khdng -+ (2, - Zr) titng -+ tdng tr'6 Z ting -+ I giim + hiOu di0n thd lri0udurrg hai dliu cudn ciiy U = I./R' * Zl giilm -+ Chon B. CLu 47. Khi con lic don dao dOng di6u hoh, "vAt qua vi tri citr bdng thi vQn tdc cqc d+i b[ng Chon B. 6p cira tu diOn v,,,"*="l2gl(1 -cosao).Thayg=10m/s2,vn,"*=50cn-)/s=0,5rn/svic{.0=0, lradtadu'ocI=7,5tn-+ CAu 48. M6t mach dao dOng di€n tir'tu do LC, kl-ri cubrrg dd ddng di€n trong mach dat cuc dai thi di€n bdng kh6ng vi i vi u l6ch pha nhau 900 *> Chon A. CAu 49. Ta c6 u^s = u + uc -> tlc = u^s - Ll = l}0.[tcos(l00nt + I00 vDcos(lggnt + nl2) - rc1Jtcos(l00.rt + 5nl6) = I00 J2 cos(l00nt 200Jtcos(100d + ru/6)cos(n/3) = 100J2cos(100nt + n/6)(V). V4y uc = 100 J2 cos(100rt + n/6XV). -+ Chon A. ' CAu -50. Quang phd lien tuc li diri rniu li€n tuc tt d6 ddn tfm chi khi vdt c6 nhi€t dd cao ( khoing & nhi€t d0 thdp, ching han & 5000C quang phd licn tuc chi c6 ving d6 -+ D sai -> Chon D. 20000C tr& lon), cdn D6p 6n dd thi thrl lAn 3(neby09/0u2011) iilL) - 100.",4sin(100nt + 4n/3) = + nl}) + 100rDcos(lO0nt - 116) = bidu thrlc diOn 6p hai ddu tu diOn Me dc 301 Me dd 302 Ma dd 303 Ma de304 I A 26 C C 26 A I C 26 D I D 26 B 2 B 27 B 2 A 27 B 2 B 27 B 2 A 27 C J A 28 D 3 C 28 D 3 D 2B C 3 B za\ C 4 C 29 B 4 B 29 B 4 B 29 A 4 D 29 A 5 D 30 B .5 B 30 D 5 C 30 B 5 A 30 B 6 3I C 6 C 31 C 6 A 31 C 6 C 31 7 D 32 B 7 A 32 B 7 B 32 D D 32 D 8 B JJ A 8 C JJ D B A -7 -t B 8 A JJ A I C 34 A 9 A 34 A 9 A 34 A 9 B 34 B t0 A 35 D 10 C 35 B t0 A 35 C 0 D 35 D ll B 36 C t1 A 36 C 1 B 36 D I A 36 B 12 L 3t C l2 A -', I B 2 A JI B 2 C 37 C t3 D 38 D 13 A 3B A 3 C 38 A J C 38 B T4 C 39 B t4 C 39 C 4 B 39 D 4 C 39 C l5 A 40 A 15 D 4A B 5 A 40 C 5 B 40 C t6 D 4I A T6 A 41 C 6 C 4I B 6 A 4I B 17 A ,1a +L C l7 A 42 B 7 A 42 D 1 B 42 B 1B A 43 C 18 A 43 A 8 D 43 D 8 A +J D t9 B 44 D t9 C 44 A 9 A 44 C 9 A 44 C 20 B 45 A 20 D 45 A 20 A 45 C 20 A 45 A 21 C 46 B 21 D 46 C 21 B 46 A 21 D 46 B 22 C 47 B 22 B 47 B 22 C 47 C 22 D 4',7 B 23 A 48 A L't D 48 D 23 D 48 A 23 A 48 D 24 B 49 A 24 D 49 B 24 B 49 A .\/ A 49 C 25 D 50 D 25 D 50 B 25 B 50 D 25 C 50 A . E€&apos ;thi thr} dai hoc ldn 3 (ngdy 091a112011) Dbo Duy Tri tr Ha Mdn: VAt li' khdi A Ngi (Thdi gian ldm bdi: 90 phitt, khdng kd thdi gian phdt ill) Ma d6 thi: 301 Ciu. vbng ddy bidn thi n ddu thi trong vbng dayxudt hidn moisudt dieridong cirn drrg xoay chid'. C- Khi cho cdc vdng day quay trong til'trudrrg cd dinh thi ;6 rhd rao. tn'thor-rg qua rndt vbng dAy bidn thi n didu hoi thi trong vdng dAy xudt hiOn mdt sudt diOn ddng chrn iirrg xoay chidu cl-rf khdng phii tD'thdng bidn thiOn ddu + B sai+ Chon B. CAu