[r]
(1)so crAo DUC & DAo rAo eUANG TRI TRUoNG rrrPr cuuytN rt quf oON
on rur cHeN Der ruynn nr/ THr Hgc srNH GrOr t op tz cAp riNn NAvr Hoc z0tg-2020
M6n thi: VAT LY
Thdi gian ldm bdi: 180 phtit
(EO thi g6m c6 02trang)
C0u I (3,0 di€m)
Ttr chAn cua mQt c5i n6m kh6i luqng M, truydin cho mQt vflt nho khOi tuqng m vAn tO" I, doc theo mfit phing nghi6ng" HQ sO ma s5t
gifia v{t vd n6m ld p, g6c gita mflt phdng nghiCng ctra n6m vd mdt
,3 ,r '"-,;" ;^, ,:.- : m
phdng ngang ld u, n6m c6 d0 cao h Bo qua ma s6t giira n6m vd mdt phdng ngang Tim v{n t6c vo cgc d4i d0 vflt kh6ng vugt qua dinh cua mflt ph6ng nghi6ng
Cflu II (4,0 diA@
D[t mpch diQn c6 so d6 nhu hinh b6n vdo mQt hiQu diQn th6 kh6ng d6i U Hai ddn gi6ng vd diQn tro kh6ng thay d6i Khi di6u chinh bii5n tro Ru ta thdy v6i hai giittri Rur : lC) vd Rbz :4C) thi c6ng su6t ctra bitin tro c6 cirng mQt
gi|triP = 25W Ddn Dr c6 c6ng su6t Pr :125W.
a) Tinh hiQu diQn this U, diQn tro R vd diQn tro m6i ddn?
b) Tim gi6 tri Rb dO c6ng su6t ti6u thU tr6n bitin trd dat gi|tri cgc d4i Tinh giatri cgc dpi d6
Cf,u III (4,0 diAm)
M6t electron dang chuy6n dQng vdi v6n t6c vo: 8.107m/s thi bay vao
mQt ving c6 tir trudng d6u UC Aay d, {ro lu6n w6ng g6c v6i cdm img tir B v6i B : 3.10-2 T Khi vdo tir trucrng, lo hqp v6i ph6p tuyi5n m{t gi6i h4n cira tt trudng mQt g6c o, : 300 nhu hinh v6 86 qua tdc dgng ctra trgng trudng Cho diQn tich vd kh6i luqng ctra electron li q, : -1,6.10-reC vir m. :9,0.10-3lkg.
a) Truong hqp d : 1,5cm, tim b6n kinh qu! d4o vd thdi gian chuy6n d6ng cria electron ttr trucrng
b) Tim d nhd nfr6t Ai5 thdi gian electron chuy6n dQng tir trudng la lcrn nh6t tim thOi gian d6
Cflu IV (3,0 diA@
M6t qui cAu su6t c6 chitit su6t n d{t trong kh6ng khi MOt tia s6ng dugc chi6u vdo qu6
cAu du6i g6c t6i i (i < 900)
a) Hdy chimg minh tia s6ng lu6n 16 kh6i qui cAu sau hai Dn khric x4
b) Tim bi6u thric g6c lQch ctatia sdng sau khi truyCn qua qu6 cAu Ap dpng sd i:600,
(2)Cflu V (6,0 di€m)
a) MQt ld xo c6 dQ ctmg 20N/m, dAu tr6n dugc treo vdo mQt di6m c6 dinh, dAu du6i gdn v4t nh6 A c6 khOi luqng 1009 Khi vflt A dang nim y6n o vi trf cdn bing thi mQt v4t B kh6i lugng 2009 chuy6n dQng tu du6i 10n v6i vOn t6c 37,5J6cmls va chpm mdm vdo vQt A Tim bi6n d0 dao dQng cua hQ vflt sau d6
b) Hai l6c dcrn gi6ng hQt md c6c vflt nho c6 kh6i luqng m: 1009 vd mang diQn tich duong q nhu nhau, dugc treo mQt noi tr6n mlt ddt Trong m6i vung kh6ng gian chrla m6i
16c c6 m$t diQn trudng d6u Hai diQn trudng ndy c6 cirng culng d0 E : 10sv/m nhtmg cic dudng sric ngugc hufng nhau Bi0t phucmg ctia c6c dulng sric hqp v6i phucrng thAng dimg mQt g6c o :
600, gia t5c trgng trudng g : 10m/s2 vd chu k! dao dQng diAu hoa ctra c6c lhc g6p !,236 lan llm q
c) Hai ch6t di6m dao dQng di6u hda dgc theo ducrng th5ng O1O2 ctng tAn sd cung bi6n dQ .l= +Jl(cm)nhrmglQch pha nhau2rcl3 Bitit Or vd Oz chinh ld vf tri c6n bing ctra hai ctr6t aiem vd OrOz: 15cm X6c dinh khoang c6ch cgc d4i vd cpc ti6u gifia hai ch6t di6m d6