i =+ = I o"o"( ,r* p* +']. v6i 1e : Qocr).
dt \ 2)
- Chu ki vd tdn sO dao clQng riOng cira m4ch
dao d6ng T :2vJLC : -f :,
=.- 2n",lLC - 2n",lLC
*fni dV l. MQt mqch dao dQng khi dilng tu di€n Cl vd cu6n cdm thuin c6 d0 try cdm L thi
in s6 ri1ng cua mqch ld .ft =0,6(WIz). Xni
dirng tu di€n Cz vd cuQn cdm tuAn thi tin s6 ri€ng ctia mqch ld /z = 0,8(MHz). Khi mach
dy dQnS dilng hai tu Cy vd,C2 ghdp.n*i.fiiip
r6i mdc vfi cu6n cam L n6i trAn thi tdn s6
dao dQng riAng cila mqch bing bao nhi1u?
Hmfng ddn gi,rti. Ta c6 l1 T=2yJLC =i +C=--l_ (l) "f 4r2f2l CrvirCzghdpn6i ti6pthi ,CC1C2l:1.] Q) Tt (1) ve (2) suy ra 4n2 f 2 L = 4nz frz L + 4n2 f] L . Do d6 f2 =.fr2 +.f? =.f =r[n *J? =l(MHz). il
*fni dV2. Trong mqch dao dQng LC c6 dao
d|ng di€n tii tqr do vdi tin sii gdc
a=2.10a(radls) . Bi€t diQn tich cqrc dqi tuAn
m6r bdn tu di€n ld 2.10-e (C). fia bidu thuc
cita diQn tich vd cwdng dQ ddng diQn trong
mach dao d)ng.
Hwdng ddn gi,rti, Chgn g6c thcri gian l: 0 h
lfc tU dien b[t rldu ph6ng di6n, khi d6
Q = Qo =2.70*e (c), ; = 0 suy ra e =0.
giCu thric iua diqn tich Q = 2.lOa oos12. tO4r) (Q.
/\
Cucrng tlQ dong dien ,:Iocosl u *!l;"(2)'
Io = eoo = 4.10-5 (e): +O(pe).
vay i : +0"o,(z.to4 t +|)fuol. o
\
D4.NG 2. Cdc bdi tQp xdc dinh ndng ltrqng di€n til trong mqch dao dQng LC li taong. Phucrng phip gif,i. Ngodi viQc nim virng c6c
ki6n thric co bin vd mach dao tlQng thi cAn
phii vpn dung duoc c6c c6ng thric sau:- N6ng lugng tliQn trucrng trong tu di6n - N6ng lugng tliQn trucrng trong tu di6n
w. : Q' : 43
"or,
( att + to\. 2C 2C --- \--- r t-
- NIng luqng tu truong trong cuQn cim w, "22: ! ti, = ! rq&r, sin2 (at + 9).
- N[ng lugng t1iQn tu trong mpch dao dQng
lil = Lr/c * 4/ 1 - 4 : ! r, l= const.
2C 2"
*Thi dg 3. Cho m6t mach dao dQng di€n ti,r
go* t, di€n co di(n dung C = 5(UF) vd mQt
cuQn cdm thuin co d0 tw cdm L = 50(mH).
a) linh ndng lrqng c{ra mqch dao dQng khi
bi€t hi€u di€n th€ cryc dqi tr€n tu diQn bing 6(v).
b) Khi hi€u di€n thd tr€n tu di€n bing a(Y)
thi ndng luqng diQn trudng vd ndng luqng t*
trudng trong mqch ld bao nhiAu? Hmims dAn gidi. a) W :
*, ,, = C(Jo
>w:Cu& 2 =5'10-6'62 2 =9.10{ (J).\'/
TORN HQC ai*ra....*r..'..rta.?.ir...t"..4.o.r.!.i...r.rr.r..rr.ir.r .r.rr. fi.fufu2.d2
b) N[ng luqng diQn truong Cuz 5.10-6./2 Wa "22=L= -''-. '' =4.10-(J). Ndng lugng tu trucrng W, =W -Wd - 5.10_5 (l).O chfi ift 2
PHAr vA rHU soxc DIPN TU
DANG l. Cac bdi tqp dinh tinh.
Phuong phSp gini. Cdn nam virng cdc n6idung co bAn sau: dung co bAn sau:
- S6ng diQn tu ld qr lan truydn cira diQn tu
trudng trong kh6ng gian. S6ng dien tu 1d.s6ng ngang, truydn qua ci chdn khdng v6i tOc d0
bing t6c d9 6nh s6ng. C6c u"cto i .,a i
lu6n vu6ng g6c voi nhau vir vudng g6c v6i
phuong truy6n s6ng.
- S6ng diQn tu mang theo n[ng lugng vi
cfrng tuAn theo c6c dinh 1u0t phin x4, giao thoa, nhi6u xp.
t'
- S6ng v6.tuy6n, nguy6n t6c chung cira viQc
th6ng tin bdng s6ng v6 tuy6n.
*fni dr1 l. Phdt bi,lu nao sau day sai khi
),
not ve song dryn tt:
A. Song di€n tir la s6ng ngang.
B. Song c6 bubc sdng cdng ngiin thi ndng
luqng cila song cdng nh6.
C. Tdng di€n li kh6ng hdp thu hofic phdn xa
cac s6ng cq.rc ngdn.
D. Tdng diQn li phdn xq cac song ngiin.
vd C ld d0 t.u cim vd tlien dung cria mqch; .X',
v ld budc s6ng vi vpn t6c ctia s6ng diQn tu.
Trong chdn kh6ng hay kh6ng khi thi
v=c=3.10s(m/s).
*fni dg 2. Mach chgn s6ng trong bQ ph4n
dd dei g6m cu6n ddy c6 d0 tU cim Io vd tu
diqn c6 diQn dung Co =24(PF).
a) Khi chi ditng Lo vd Co thi bdt daqc s6ng co
badc s6ng,a6 :100(m). T{nh Ls (toy n'= 10 ).
b) Ghdp th€m vdo Cs mQt tu xoay c6 di€n
dung C*vri; l(pF) <C. <1,6(pF), d€ bdt bdng
s6ng ngiin. H6i tdn s6 cila bdng song ndy
biiin thi€n trong khodng ndo?
Htai+tg dfin gidi. a) Ap dung c6ng thric
lv
_---- =- SuVfa
2n,,!Loco 2
,_ 1& _ 1002
"u - nrrrco 4nz.(3.lor)' .24.10-tz= 1,16.10-4 (H). = 1,16.10-4 (H).
b) Ki hiQu C ld diQn dung tuong ducrng cira b6
tU ghdp n6i ti6p Covd C,,ta c6
1.24 )4.
Cr =C-io =ffi=fi(nr);
cz=c*=##=t,5(pF).
Hudmg dfin gi,fiL.Nlng luqng cria s6ng tliQn .fo m
tu ti le vdi t6n 19.tu.:gng..fti budc s6ng V=tl r-^ =
cua s6ng cing ngin thl tan so cua song cdng Jt Y \'0
l6n, n€n ning lugng cria s6ng cing l6n.
V4y d6p 6n B sai. E
DANG 2. Cdc bdi tQp dinh lffqng.
Phuong ph6p gini. - Y0" dung tluoc c6c
bieu thuc x5c dinh tAn s6, chu ki, n5ng lugng
cria s6ng diQn tu.
- Mu6n thu hay ph6t s6ng diQn tu thi m4ch
dao tlQng ph6i c6 tin sO ri6ng bdng tdn s0 cira s6ng/16,,, :.frdoenuY
-J- =! trong d6 L
znJ tc ).
Tir c6ns - - ----o ----'- thkc f r znJ rc suv ra
v 3.108 tlt- nl:===-Jr =5lo v01 yb ) .fo = = 3.106 (uz) = 3(MHz). 100 Yqy f,= 15.106 (Hz) = 1S(MHz)' "fo - "f, Suy ra -fz=4-fo=12(MHz).
Vflv tdn sO bii5n thi6n trong khoing
12(MHz) <f<15(MHz).tr
lt1
_t
-{G -A
TORN HQC r.rf ..*..r..r.....r...r........4.c..r.r...ii...rr....r!..r ...... fifu,wvd|
FAAA,
iE#Ti Cfti .ffiF i}I$fr ,IfCfi TICC
rrrcuyEr.r rHANH HLING - lrcuvEru rHr u6ruc rHUy
(GV THPT chuy1n Le Qu!,DOn, Dd Ndng) ni tQp v0 C6u t4o nguy6n t(r thuQc dpng
bii li thuyCt chir dao nh[m trang. bf cho Ldi gidl
Vfly ki hiQu nguy6n til Ara t[O. n
*fni dU 2. Trong phdn ti'hop char MX2,
;:
tdng so hat co' ban la 140 va so hat mang
diAn nhiiu hon s6 hat kh6ng mang di€n la 44. SA tnAi _^ : cua X lon hon tA tnai , cua M ld 11.
Tirtg s'6 hat c'o' ban trong X nhi€u hon trong
.\,1 lit 16. Xac' dinh ki hiQu nguy€n tu' M, X vd c6ng rltil'c' phun tti' ltLY2.
Ldi gidl Gqi a, b, c, d 16n luqt ld, ZM Nm Zx
Nx.Ta c6 hQ phuong trinh
l2a+b+2(2c+d)=149)Za++c-(b+2d1=44 )Za++c-(b+2d1=44 )c+d-(b+a)=llt' l2c+d-(2o+b)=16. h=12 . (c:17 urar n9 trm ou-o. c \o =tz ,u [d = ts.
vgy Mtdll*r, xullct viLvtxrldMscl2. D
Trudng hqp bdi todn cho fi"g tO hqt cdc loqi
nhtmg kh6ng ffi dii ki€n dA hinh thdnh hQ
phtmng trinh hai dn hodc b6n iin nht trudng hqp ffAn thi cd th€ s* &fig thAm kidn thwc sau: Th6ng throng, dihva cdc ng,tyAn fi c6 Z < 82 ,
M
thi l<-- <1"524.
Z
Gpi S ld tiing td hqt cdc loqi: S:22 + N
+N: S-22 = ZSS-22<I,5242.
^ s _s
Suyra - 3,524 < Z <-.3
l2zn+Ne=24
I;,^='#;;;={i::i
ngudi hgc nhirng ki6n thfc co bin vO thdnh ph0n cdu t4o cira nguy6n tu - kh6i luqng
nguyOn tu -.nguy6n tO ho6 hgc. Ddy ld nhirng
nQi dung ki6n thric cty s0 v6 ctng quan trgng
dO nghiOn cr?u tinh ch6t cira c6c chAt cf,ng
nhu nhtng img dpng cira chring.
1. CAU TAO NGUYUX rrr
(lu : ltlvC : I,6ffi5 1A2a gurt; eo : 1,602.1fr" q. Cdc bdi todn liAn quan ddn s6 lt qrg cdc hqt co bdn thtdng liAn quan ddn hai UAn sii m sA
proton Z (bdng sd electron) vd s6 notron N. Cdch gidi th6ng thudng ld lqp vd gidi hQ phaong trinh bdc nhh hai dn @ho mQt
nguyAn fi|) hofic b6n iin (cho hQ cdc nguyAn
^:,
tr cua hai nguy€n to).
*fni dg 1. tVguy€n tir A c6 dng sd hor ,o
bdn (proton, no'tron vd electron) ld 24, sij hqt kh6ng mang diQn chi€m 33,33%. Xac dinh ki
hiQu ngttyAn ru'A.
Cdu tqo nguy1n tir xn6ituvttg DiQn tich
Hat nhAn Proton mp = '1,6726.10-24(9) = 1 ,0072 u = 1 (u hay dvC) qp = +1,602.10-1s(c) = 1 + (+eo) Nohon mn = t,62n8.10-24(g) = 1,0086 u -1u 9n=0 V6 elechon Electron m.= 9,'1.10-28(g) - 0,00055u qe = -1 ,602.1 0-19(c) = 1- (-eo) ,4.
TOfiN HQC .reo*soi**6**8.*6s&.$s**&sr**..ffi.eee.s6ce.os.s&e8*6.*ie.q& **rn** fidosanr$d2
*Thi du 3. a) T6ng sd hm cdc loqi cua KhOiluqngri6ngciranguy6ntuhittrold
nguyan ni' m6t nguy€n n n m B. Xdc dinh ki D =L -1,6736j0: x 2,685 (e/" 3).
hiQu nguy\n ttr R. V 6,233.10-25
b) TonS t6 hot cac loai cua nguyAn nb mil b) ThC tich cira hat nh6n ld
;i#;;';,y;;r^f, r',!l,,f,Y;;XioY;"0 v =!nR' =!x3,'\4x(,,, ,0-,, * o:)
Ldi gi,rti
a) Theo gi6 thitit 2Z*+ NR: 13.
uat fix3,6e< zR <f =+'::'
Suyra Zp=4,Np=5,An=9.
Ki hiQu nguy6n tu R ld lBe.
b) Theo gi6 thi6t ZZy+ Nu:40.
u[t ffi= 11,35 < zM ,**13,33.
YOi ZM: 12 th\ NM: t6 = Aru:28 (loai).
YOi Zva: 13 thi NM: 14 s A1a:27 (tthfln).
Ki hiQu nguy6n t& Mld 11Al .
*fni dU 4. a) Tinh khoi lrong riAng Qheo
g/cm3; ct)a ngu-vOn tti hidro. BiAt ban kinh
ctta nguyAn u H ld 0,534 ua H : 1,0079.
b) Giii'a ban kinh hat nhan (R) va .rA khdi ,rio
ngu.v\n tu'lA) co moi lien he
I
R : 1,5.l0-13 x ,El (cm).
Tinh kh6i lrqng ri€ng cila hqt nhan.
c) Giai thich vi sao kh6i luqng riAng cila hatnhan lqi ktn hon ,At nhiiu so voi kh6i ltrqng nhan lqi ktn hon ,At nhiiu so voi kh6i ltrqng riAng cira nguyAn tib?
Ldi gidL a) ThO tich cua nguy6n tu hidro ld
l4
V = -nR3 = -.3,14.(0,53.10-8 cm)l ^a
JJ
- 6,233.10-zs 1cm3).
fh6i luqng cira mQt nguyOn tu hitlro ld
m : 1,0079 x 1,6605 JO'24 = 1,6736.1024 (g).
=1,413.10-38 x l(cm3). fhOl tuqng riOng ctra hpt nh6n ld
D =* - Axl'6605'10)a = l,l75.l0ra(g/cmr).
V 1,413.10-r8 x I
c) KhOi lugng hat nhAn gdn bdng trrtrOi.luqng nguyen tu (chi chdnh lQch mQt lugng rdt nh6,
UXng UlOi ioqng c6c.hqt electron), nhmg th6
tich hat nh0n lpi rAt nho so vdi the tich
nguyOn tu (b6n kinh hat nhdn gAn bing
1/10000 b5n kinh nguy6n tu) ndn kh6i lugng
ri6ng h4t nhdn 16n hcrn rdt nhi6u so vdi
nguyCntu. D
2. KHOI LLTqNG NGUYTN TU
- XltAi hrqng nguyAn u ny€t diii 1m' (g)) cta mQt d6ng uicu tfi6 dugc x6c dinh bing t6ng
ttiOi tuqng c6c hat proton, ncrtron vd electron c6 trong nguyOn tu. Trong tinh to6n g6n dring
thuong bo qua thOi luqng electron vi chfng
c6 kh6i luqng r6t nho so v6i proton vdnotron. notron.