GIẢI CHI TIẾT THI LÝ L4-2011(ĐDT HN)

,f
'
\ {^/'
t
l;" t*
-uLh,-
I
Vo,{.
Hnfng
din
gifri
Od
ttri thfr 6n
4 -
ngiy 2712/2011
Mdn:
Vit li
-
Mi d6
401
CAu l. Mhu do
cria
rubi
do ion cr6m
ph6t
ra khi chuyOn t* trang
th6i kfch thich
vd tryng
thr{i
co bin
->

Chqn
A
Ciu 2. tin sO
g6c
ro
:2nlT :2n10,4:
5n(radls),-+
DO bii5n
d4ng
cria
ld
xo khi v{t
cdn beng
Al
:
glio2
=
l0(5n)2
=
4cm.
Khi ttua v4t dtin
vi tri ld
xo
kh6ng bi6n d4ng rdi
bu6ng
nhg thi biOn ttQ dao
cl6ng c0a
Pg,e-
vqt4=Al=4cm+chi6udei
l6nnh6tctraldxoldl.u*:10+Al+A=40+4+4:48cm-+ChqnB.

CAu 4. Theo bii to uys vi une lQch
pha
nhau 600+ ues tr6
pha
300 so
vdi
i;
u4p
lgch
pha
750
so
vdi uAs -+
ueN
l€ch
pha
450 so v6i i
-+
ta
c6
gidn
tl6
vecto nhu hinh v6.
Tir
gidn
dd vecto
-+
Un: UnNcos45o = 60
Ji
lZ:30JrV

>
u.ce
=
unlcos3Oo
=
loJi l(Ji tzl
=
20
J6
v-+ chgn B.
Ur.,ts
CAU 5. Trong m4ch
dao
tlQng
di6n tir
:
Di$n tich cria tg
diQn
vi cudrng
tlQ ddng
diQn
trong
m4ch
lQch
pha
nhau
900-r
A
sai. Cuong tlQ
ddng

dipn trong m4ch vi ndng lugng
tir
trudng trong cuQn
cAm cfrng nhu
diQn
tich
cira
tp itiQn vi nlng
lugng <tiQn
truong cria tp
diQn khdng
bi6n thi€n cirng
tin s6 n€n kh6ng
th6
so
sdnh
pha vdi
nhau-+ B vd C
sai.
Cuong
dQ
ddng
di€n
trong mgch vd
cdm
rng tir cria
t&
trulng
trong
mpch

bi6n
thi6n
cing
pha+
D
dring
+ Chgn D.
CAu 6. Khi min
cfch m{t
phing
hai
khe le D thi khoing vdn li
i
=
},Dla
=
916
=
l,5mm
(l).
Khi mnn
dlch
di 0,6m thi
khoing
vdn
li i'
=
914,5:
2mm
-+

i'> i
-+
D'>
D-) D': D
+
0,6 -)
i'
=
l,(D
+
A,6)la
(2)
-+ Tir
(l)
vn
(2)
-)
(D
+
0,6)/D =211,5
->
D: 1,8m. Tir
c6ng
thric i= ]"Dla-) )r.: ialD
=
1,5.10r.
0,48.10-3/1,8
=
0,4(pm)
-+

Chqn B.
Cdu
7. H4t a c6 kh6i lugng
lon hsn r6t
nhiAu
so vdi
hpt
p
ndn bi lech
it hon so vdi hat
B
khi
ditrong dign
trudng -+ D
sai
+ Chgn D.
Cdu 8. t
Mric culng ttQ
dm d B nho hon
d A
20dB
-+
cudmg <tQ
Am d
B
nho
hcm d A le 102 lin
-+
Ia/ls
:

(SB/SA)2
=100-+SB/SA=10;lellc:(SC/SA)2=[(SA+SB)/2SA]2=(l+SB/SAF/4:ll214=30,25+ChonB.
Cdu 9. Lpc ma s6t
sinh rac6c h4t mang tliQn n6n c6
tuong
t6c tlign tt
+ Chgn D.
Cdu 10.
Chgn
gdc
th6 ning
o
v!
tri
cin bing, khi vflt d dQ cao h
=
FV3 thi th6 ndng cira
vft
bing ll3
cs
ndng
-+
EQng
ning cria vft
bing
213 co n6ng
-+
mv2l2
= 2(mv,u*2lZ1l3 -+
vz

=
2v*
]B
-+
v
= 2v
^
*2
I .11
:
301
Ji
=
I
0
rE
cm/s
x
17,32
cm/s
-+
Chgn B.
CAu I l. Tirc6ngthirc
i==)tD/a,thay tr
=clf
-+
i:cD/(fa)
+
Chqn
D.

Cdu 12. Tg
C ktrdng ti6u
thu cdng sudt
nOn cdng sudt ti€uthp
cta do4n m4ch
AM
li c6ng
su6t ti6u thp
tr6nbii5ntr0,khitl6tli€ntrdcriabi(introp=,[;a17-2.y=@=40o.T6ng
-
trd
cta mqchZ=
J(r+
R)2
+
(2,
-
zr)'
:./1zo+40)2
+(60Jt
-40Ji)'=
40rEQ + cudng
<t0
higu
dpng
trong
mach
bing |

UIZ

:
6Al$0.16)
:
Ji
tZ1t1-r
C6ng
sudt ti0u thp tr6n dogn mgch AM te
p
=
I2R
:
(Ji
tz'12+0
= 30w-+
vay
R:40o;
p:30w
-+
chgn
A.
Ctu 13.
TrOn mQt
ddy ttin h6i,
s6ng
t6i
vi s6ng
phin
x?
ngugc
pha

nhau t+i dAu c6
ainn chfr
khOng
phni
t4i UAt t<i
di6m nio nOn
D sai + Chgn D.
Cdu 14. Tai
thdi
<li6m t
=Tll}thi
cuong tt$ ddng diQn
trong mqch
bing i
=
8cos2nt/T
=
8cosn/6
=
4"6mA.
Tt c6ng
thric
(i/ls)2 +
(uru0)2:
l-)
$Jl
tqz
+
(4/tjo)2:
l-) hipu

tlign
th6 cuc
ttsi
giiia
hai bin
tU diQn
li Uo:8V.
Ta c6
CUo2: LIo2
-)
L
=
CUozlti
= 5.10-e.82/(8.10r)2:5mH
-+
Chgn C.
Cdu 15.
Tia tri
ngopit6c
dung l6n
cdc
lo4i
kinh
inh
n€n cflng tdc dung
lOn kinh
inh dO chpp
inh
ban dOm
+

A dirng. Cdu B
vi D
dring
(SGK
VLlz).
Tia tti ngo4i cfing tic dung
nhiQt
-+
C sai
-+
Chgn
C.
CAu 16. Ning luqng
c0a
m6t xung
5nh s6ng laze
W
:
P.t: I 0.200.1
0-e
:
2.10-6J-+
56
ph6t6n
chtia
trong
mSixung6nhs6ngbingN:W(hcl}.):WV(hc):2.104.0,64.rc-646,625.10-34.3.108;=
6,44J012
h*t-r
Chgn A.

Cdu l
T.Khohngthdi
gian
ngin nhdt dd
vat
di tt.UiCn
niy dlin bi6n
kia
bing mQt ntia
chu
ki dao
dQng
cria
vft
chri kh6ng
ph6i
khoing
thdi
gian
b6t ki
-+
C sai
-+
Chqn C.
C6u 18.TirdiAukiQndAubnitac6phuongtrinhphdnung
in*
iD-+lT+
jn.N[nglugngmiphin
img toi ra
lA

W:
(2mo-
m1- mn)c2
:
(2.2,0136
-
3,016
-
1,0073)uc2:0,0039.931
= 3,63(MeV). Kh6i
lugng
nu6c n{ng
D2O trong.lkg
nu6c tg nhi€n li 0,015%.1000
= 0,159
+ sO hgt
D2 bing
0,15.6,022.1023n0
:
4,5165.102rhpt.
Theo
phin
ung hat nhdn
tr6n thi
crir c6 2 hqt
Dz thi cho
ning lugng
3,63MeV
-)
t6ng ning

lugng
thu duo.c bing 4,5165.102t.3,63MeV:1,6395.1022MeV
=
1,6395.1022.1,6,10-r3J
:
2,624.1OeJ
=+
chgn A.
Cdu
19. A. M4ch
dang
c6
cQng hu6rng
thi
culng tlQ
hi€u dgng
cria ddng
diQn trong
m4ch d4t
cgc
ctgi,
khi
ting
tAn si5
cia
ddng tliQn
thi cuong ttQ
higu
dgng
ddng diQn trong

mach
giAm
-r
A
sai. + Chgn
A.
B. Vi
Z
tlng
n6n hp
s6 c6ng
su6t
cria do4n m4ch
gidm
+ B dfng,
C. Khi
Tach.
c6 c$ng hy*g.
s5 chi
cia v6n t<ti ti ruong mfc.
giira
hai ttAu
dopn mach
g6m
tu diQn vi cuSn
cim thuAn bing
0, khi
tAn
sti f thay OOi ttri st5
chi cia v6n kri tang

+ C
rhing.
D.
Khi cQng huong Zy=
Zc, khi
tdng
f thi
ZLtdng, Zg
gi6m
mi I
gi6m
-+
Uc
:
lZg
gihm -+
D tlirng.
Cdu
20. 6nh sdng don sic khi di
tir
kh6ng khi vio trong nu6c thi
budc s6ng
giim
?"
:
Mn
=
0,61(413)
=
0,45pm

-+
khoing vdn i
:
),'Dla:
0,45. rc4.21(0,5.10t') =
l,8mm.
KhoAng c6ch
gifra
hai vdn
sSng bflc
ba
tr6n mdn bing
6i =
6.1,8
:
l0,8mm
-+
Chgn D.
CAu
21. ROto cria
ttQng
co
kh6ng tl6ng bQ ba
pha
ld r6to lOng
s6c chf kh6ng phdi
ld nam chfrm
diQn+ C
sai-+ Chon C.
Cdu22. D6i

trr,rc toa
d0
X:
x
-
I
=
4cos(srlt+ rcl6) cm.
Khi
x:
-l
cm thi
X
=
-2cm.
Trong
gi6y
diu ti€n s6 chu
ki
bing
llT
:
110,4
=
2,5it&c
li trong 2,5
chu
ki dAu tli€m M
quay
duo. c

2,5
vdng. tvtSi
vdng
quay,
di
qua
di€m
N
(c6
X:
-2cm,
theo
chiAu
duong)
I
lAn, trong
2 chu ki M
<li
qua
N
.le
2
lAn,
cdn
l/2
chu
ki
nta
thi
M chua

qua
N,
do v4y sti
tAn v$t
qua
tli€m N chi ld 2
+
Chqn
A.
Cdu 23. Trong mpch
dao tlQne di€n tir tU do, vu
112 chu ki dao ttQng
te
tir
ktri
ddng diQn d4t cgc d4i, n6
lai
ttat
gi|tri
cr,rc dpi n6n
ning lugng tir
trudng v6n d4t cgc d3i
-+
ndng lugng
cria mpch dao tlQng t4p
trung
d cuQn cAm
+ Chgn A.
Cdu 24.
Tri

thdng
cUc Aai
qua
khung dAy bing Oo:
NBS
:
50.0,2.
7,8J0-2
= 0,78(Wb). TAn
s6
g6c
cria
tir thdng
bing t6c dQ
g6c
quay
cia khung
tD: 2nn
=
8On(rad/s)
-r
biAu thirc
cria tir th6ng
qua
khung
O
:
0,78cos(80rt
+
n/6)Wb

+ sudt
tliQn tlQng tr€n khung li e:
-
dQ/dt:
0,78.80nsin(80rt
+
n/6)Y
:
l96cos(80nt
-
n/3)
(V) -+
Chgn A.
C6u 25.
Theo thuy6t lugng
trl
c6c
phdtdn
c6 ning lugng e: hf
->
c6c
ph6t6n
c6 tAn
s6
kh6c
nhau
thi c6
n[ng
lugng khdc
nhau + B

sai
-+
Chgn B.
Cdu26.
DOng nlng
crla mdi
Olectron
k*ri
dlSn an6t
li Wd: eUar:
1,6.10-re.12000:
1,92.10-r5J.
56
Olectron
tt6n an6t
trong m6i
gi6y
ln n=lle= 20.10-3(1,6.10-re)
=
1,25.1017h4t.
56 electron d6n
andttrong
20
phrit
li N
:
n.20.60
=
1.5.1020
hat. NhiQt lugng mi

an6t nhgn
duo.c li
q
:
90olNWd
=
g0%1,5J020J,92.10-rsJ
=
2592001
:2s9,2
kJ
-;
Chgn
B.
CA.u 27.
Trong c6c
lo4i tia
ph6ng
xA
thi tia
gamma
khdng
mang
diQn, cdn
cdc tia cdn l4i
mang tliQn tich
n€n tia
y
kh6c
vdi

cic tia
cdn l4i
-+
Chqn D.
Cdu28.
Tai
t:
0
(diCm
M tr6n
duong
tron)thi x:
0
-+
dQng
nlng cfia vgt
dat
cuc d4i
vd
th€
ndng bing
0.
Khi l14
ddng ndng chuy6n
thdnh th6 ndng
thi
thd ndng
bing
ll4 cs n[ng
+ ll2kxz

:
ll4.(112)kA'
-)
x': A2l4
-+
x= -Al2
-+
khoAng thdi
gian
niy
li khodng thoigian v{t tti tri M tttin N
tr€n
dulng
trdn
t1,a51
:
Tll2:
(Znll0n)112:
1160s + Chgn A.
Cdu29. Mdy bi6n 6p li
m6t thi6t
bi
ding de Ui'5n aOi diQn 6p cria
ddng di€n
xoay chiAu vi
giir
nguydn
tAn s6 c0a ddng diQn xoay
chi€u
n6n

A sai
+
Chgn A.
Cdu 30.
Trong
quang ph6
cfia
nguyOn
tft
hidr6,
b6n
kinh cria
quT
dao
c6
mftc
ndng luqng kich
thich
thir
hai ld 1
,44a,
d6 le ban kinh
cria
quT
d4o
M c6
b6n
kfnh 9ro-+ b6n kinh
Bo bing
rs:

1,44a/9
=
0,16a. B6n
kinh cria
qui
dqo c6 mfc ndng lugng kfch thfch
thf 4
(qui
ttao O)
bing 25rs
:25.0,16a=
4a -+
Chqn
C.
C0u 3 l. Chc hgt t4o ra trong
m6i
phOng
x4 li x6c dinh, con c6c hat
t4o ra trong
nhirng
phdn
h4ch kh6c
nhau cria cDng m6t
ddng
vi
ld khdng
x6c dinh.
-+
C sai + Chgn C.
CAu

32.
Ban dAu
m4ch cQng huong
voi
s6ng di€n
tir
c6 budc s6ng
60m
-)
Xr
:
c.2n [LC:60m
(1).
Khi tdng
C
th€m
6pF thi budc s6ng
)u2=
c.2n.JTG+6pn= l20m
(D.
LaV
(2)
chia cho
(l)
-+
(C+6pFyC=4-)C*6:4C-+C=2pF.KhigiimCdi
lpFthi diQndungcdnlpFnghialiCgi6mdi
mQt
nrla,
cdn

Cl2. Khi tdng L
l0n 18 lAn vd diQn dung li
Cl2
thl
budc
s6ng cQng huong ld
}4
:
c.2n.
JISLC
I 2 = 3(c.2n.JtC
l=
3.60
=
l80m + Chgn C.
Cdu 33. ChiAu
ctia
vectcr v{n
tdc
thay d6i khi'vdt
qua vi
tri bi6n
*r
A sai
ChiAu cria
vecto gia
t6c thay
d6i
lJri
vft

qua
vitrf vi tri c6n
bing
-+
B
sai
ChiAu
cria
lyc ttdn hdi thay
d6i khi
v|t
qua
vi
tri ld xo
kh6ng
bitin
d4ng
-+
D sai
ChiAu
cria
lgc k6o vO
thay tl6i ktri vflt
qua
v!tri
cAn
bing vi lgc k6o
vd lu6n huong
vA
vi

trf cAn
bing
->
C tlirng
+
Chgn C.
Cdu 34. Di€m M nim
trOn vdn cpc
ti6u,
gita
M vi <tuong trung trgc
c0a AB
c6 2
viln
cpc ti€u kh6c
-+
M
nimtr€n
vdn cpc
ti€uvdi k=2-+
dz-dr
=(2k+
l)M2=(2.2+
l)Llz=37,5-30=
7,5cm
-+
5]"12=
7,5cm-) l.
=
3cm

-+
S6 Aiem
"u,
aei
ntrGu ntr6t tr0n ttopn
itring Oai
L trongkhoing
gifra
A va
n iing
phin
nguy6n cta thuong
s6 tt(UZ)
cQng th€m L Ta c6 Ll(M2)
=
17,25/1,5
=
I 1,5
+ 56 itiiim cgc tt4i
nhiAu
nh6t bing 12
-+ Chgn C.
Cdu 35. Trdn thang
s6ng
diQn
tir,
thti
t1r
_c6c
brtc

x4 theo
sg tdng dAn
cria tAn s6 lar
Tia hdng
ngopi, tia tri
ngopi,
tia
Ronghen,
tia
gamma
-+
D
dirng
+
Chgn D.
C8u
36.
fhdi luqng
m4t trdi
giim cdn mQt n&a, tuc li
gi6m
tli l030kg.
Theo cdng thirc Anhxtanh khdi
lugng
niy tuong
ung
vdi ndng luqng E
:
mc2
:

1030.(3.1 0t)t
=
9.1046J
-r
Khoing
thdi
gian giam
di
phAn
ndng
lugng
niy
blng t
=
E/P
=9.10461(3,8.1026)
=2,386.1020s
=
7,51.1012 nlm
-+
Chgn
B.
CAu 37. TAn s6
nh6 nhdt cria 6nh sang
kich thich d€ €lectron
bft kh6i bA
ryt
kim loai ld
6
:

Aftr
=
4,8.1,6.10-rerc,626.10'3a
= l,l6.l0r5
Hz-+ EiAu ki€n d6 €lecrron
bat kh6i,bd m{t tAm bac li
f> l,l6.lOrsHz-+
Chgn A.
Cdu 38. Trong hiQn
tuqng c$ng huong dao il$ng co, bi6n tlQ dao dQng
cu0ng
btic tlSt cgc dgi mi tOc AO
ti0u
hao ning lugng
do ma s6t
beng
t6c dQ cung c6p ning lugng cho h-6.(SGKVLI2)
-+
B sai + Chgn B.
Cdu
39. Khi ttiQn
6p hiQu dqng hai dAu
cuQn
cim
dpt
gia
tri cyc tlqi
thi tlign 6p hai <tAu
tto4n
mgch

gtim
<liQn
trd vi tr,r ttiQn
ntii titip l$ch
pha
vdi iliQn 6p hai ttAu do4n mach ld
900
-+
ta c6
gian
dd vecto
nhu hinh v6.
Tir
giAn
ttd
vecto
-+
Unc
=
Jq:fi=
![20t
-60'
= oor6V;
coso
=
Unc/Ur
=
AOJi
ttZO
=

.l-l
tZ*>
cr
=
nl6 +
ug
tr6
pha
so
vdi
uns li
n/6
+
nlz:2n13
-+
pha
ban tliu cria
iliQn
6p u6 bing nl4
-2n13: -5nll2.
O
Ta c6
Us
=
Upscosn/6
=
60\6 .Ji tZ= 90V
-+
Bi6u thrtc
cria ttiQn

6p hai dAu
tp
ttiQn li
-+
us
:9}Jicos(l00nt
-
5n/12)Y-+
Chgn C.
Ciu 40'
Tai nhfrng
diiim
tr6n vdn
ctrc dpi ld
chd vdng
ggn
l6i g?p
vdng
ggn
tOi
-+
a dring
-+
Chgn
A.
T4i
nhfng ditim
tr€n vdn
clrc
dpi cfrng

li
ch5
uong
gqn
l6m g?p
vdng gon
l6m
-+
B
sai.
Tgi
nhirng
diiim
kh6c
nhau
tr€n
vdn cr.rc dai
n6i
"nrng
pha
ld kh6c
nhau
+ c sai.
'
T4i
nhtrng
di0m
kh6c
nhau
tr€n vdn

cr,rc ttpi vi
vAn
cr,rcti6u
n6i
chung
pha
li
kh6c
nhau
-+
D
sai.
Ciu 4l.
tchi duu
<t6ng
ho qu6
l6c
tir m4t d6t l€rtniri
ruo ooor
thi;dg'hd
.iiv
rrrar
ai rai
nliy
aem
ra
l,l
l8s
-+
Ta c6

86400
[o(t"
-
ta)/2
+
h/R]
=
[,it8
-+
86400
[2.10-:(h
-t^i2
+
0,616400]
I
i,ilg
->
0,864(tn-to)+8,1
=l,ll8-+(t"-td)o-80c+nhiQtd00mata6t(ta)lonhonnhi6t<lgtr€nniri(tn)li
8oC
-+
Chgn C.
C6:ll
42. Tia s6ng
d6
truyAn
trong thuj'
tinh c6 budc
s6ng
tit 0,64/1,6

= 0,4pm
dln
A,7611,6
:
0,471pm -+
trong
thui'tinh
tia
sdng
dd c6
budc s6ng
tir 0,4pm
ddn A,4751tm.
Tia
sring
ving
truyAn
ftong
ch6n
kh6ng
c6
budc
song
tir
0,57pm
d6n
0,6pm. Tia
s6ng tim truyAn
trong
nudc

c6
budc
s6ng
tt
0,4 4l(4/3)
=
0,33pm
diSn 0,38/(413):0,285pm
+
trong
nu6c
tia s6ng tim
c6
bu6c
s6ng
tir 0,285prn"dtin
0,331rm.
So
sdnh
c6c
k6t
qui
tr6n
ta c6
l.v >
ID
>
l.r
-+
Chgn

A.
(Thi
sinh c6
thiS
chgn
fit
n
gia
tri nio
trong
i<hodng
cric
budc
s6ng
vi
thr,rc hiQn
c6c
phdp
tfnh
nhu
trOn cfing dugc
k6t qui
cAn tim)
Ciu
43. Thi€n
HA
cria chfng
ta c6 dulng
kinh
bing khodng

100000
nim
6nh s6ng
(SGKVLI2)+
C
dring
-r
Chgn
C.
Cdu
44.
Sti hat
nhdn
!f
Co
c6 trong
I 00g ban
ttAu bing No
=
100.6
,022.102316A
:
1,A0367
.t
O2ahpt.
S6 trat
B-
ph6t
ra
trong

thoi
gian
t
ld No
:
Noe-r'
:2,497.10t7;
thay
gi6
tri
No vd
t
:
I phrit
-+
hing
s6
ph6ng
xg
l,
=4,146.10-e(lA)-+
s6hatF-sinhratrong
I n6m
ldn
=No-Noe-rt,vdi
t=
I nim
:iAS.z+.leOor-
n: 1,23.1023
hat

-+
Chgn B.
CAu 45.
Di6m
M
nim
trdn
AB c6ch
trung dirlm
O cria AB
lA
2 cm
-+
higu
rluong
di dz
-
d1:2.)
=
4cm.
Vi hai
ngudn
A vi
B ngugc pha
nhau
n6n bi€n
clQ dao ttQng
t4i
mQt
rliem

udt
ti ii A
:l2acos[
n(dz
-
dr)/1.
+
nl2ll
:l2.Zcosl4nll,2+
nl}ll=
l4cos[l
tnl61:2Jj"
+ Chgn
C.
CAu 46.
A. C6ng
sudt tiOu
thp
clign cria do4n
m4ch li
t6ng
cdng sudt
ti€u thu
tr0n
c6c
ctign tro
thuAn.
+
A
tlfing.

B.
CuQn
cim.
thuAn
vi tp
dign kh6ng
tiOu
thg
cdng su6t.
+ B rlirng.
C.
Khi
miic nOi tiiSp
th6m vio
m4ch
m6t cuqn
cam
thuen hlV mOt
tu
iien
thi t6ng
r&
thay AOi
ung
ho{c
giem
tu!
thugc
gi|tr:i
cincim

khdng
vi dung
khang
n€n c6ng
sudt c0a
doan
mach
c6 th6
ting
ho4c
giAm.
-+C
rtung.
D.
Khi
mic ndi
ti6p
thOm vio
m4ch
mQt dien
tro thuAn
thi ilign
trd
ctia
mach
ting +
tOn!
trO ting
-r
cuong

clO hiqu
dpng
cria ddng
tliQn
qua
mgch
gidm -+
cdng
sudt
cria
doqn
m4ch
cd th6
ting hoac
giAm
-+
D
sai -+
Chgn
D.
Cdu47.
DiQn
6phiQudpnghai
dAudo4n
mgch
bingU
=
JUtr+(UL-Ur),:
ofOd
+1tZO-OOy:

60JiV.KhitAns6lif,ta
c6ZylR:UlUn:120/60:2;Zc/R:tJclUn:60/60-l.Khitans6lefl2thi
Zt':ZJ2;Zc':2k-+
U1'/Up'=Zr-'lR=hJ2R=
l-)UL':fJR'
;IJc'/[JR'=
k'tR=2ZglR:2)
Ug'=2Un].Tirc6ngthfrc(!lpl)2].(Ur'-Uc')2:Ut-(ul')'+(unf=u2-+2(Un')2=u2-r(Un')2:
U2/2=
602-+
tliQn
dp hai
dAu
diQn trd
bdy
giobing
Un':60V
-+
Chon
A.
Cdu
48. A.
anh
sdng
tring li
h6n hgp
cria
c6c
rinh
s6ng don

sic
c6
miu
biiin
thi6n li6n
tgc
tir tl6 d6n
tim
chft
kh6ng phii
chirm s6ng g6m
c6
biy tia
s6ng <ton
sic ttr miu
dd
d6n
miu tim
-r
A sai.
B.
Mqi
rinh sring
clon
sec mi
ta ntrin ttrdy
ttAu
co bu6c
song trong
khoang

tu
chrmg
0,38
pm
d6n
0,76
pnr
tong
ch,6n kh6ng,
chf kh6ng
phii
trong bdt
ki m6i truong
nio.
-+
B
sai.
C.
Khi
di tt m6i
truong
kim
chi6t
quang
sang
m6i truong
chi6t
quang
hcm thi
chi6t

sudt t6ng
-+
t6r
AO
truyAn
s6ng
gidm
+
budc
s6ng
c0a
anh s6ng oon
s6.
giam
ai
-+
c
itring.
Vfly
chqn
C.
D.
Khi di tir
m6i
trudng
trong
su6t niy sang
m6i trudng
trong
sudt

khdc,
tia
sang
c6
budc
s6ng
cang
ldn
thi
chitit
sudt c0a
m6i
trutmg
aOi vCi tia
s6ng
cdng nhd
+ tia
i6ng
b! lQch
cang
1l D sai
Cdu
49.
Sau 2
nim
mQt lugng
ch6t
ph6ng
x3
gidm

tti 4
lin,
d6
ld kho6ng
thoi gian
bing 2
chu
ki b6n
rd
-+
2T
:2ndm
-+
Chu
ki b6n rd T
:
lnim
+ Sau
3 ndm
=
3T thi
kh6i
luqng
ch6t ph6ng
xa
cdn
m
=
mo/23:
m0/8,

tr?c ld
luqng
ch6t
ph6ng
xq cdn
lai l/8
lugng
ban
dAu
+
Chgn
C.
Cdu
50' A.
MAt
trcri
ph6t
ra
quang
phO
tien
tuc
vi
d6 le
kh6i khi
c6
6p
su6t
lon
n6ng

s6ng ph6t
ra
-+
A d[ng.
B.
Quang
ph6
cfia
m{t troi
thu
duoc
o
tnii ddt.li
quang
phd
hdp
thu
vi
6nh
sring
m{t
trdi
khi di
qua
lop
khi
quy€n
mdt
trcri
bi lop

ndy h6p
rhs n€n thu dugc
quang
phd
h6p
thg.
+ B drin!.
C.
Quang
pho
trdp
thu
cria ch6t
iong ld
quang
ptro
dam,
m5i
Oam
g6m
nhi€u
uaitr
tt6p
thp n6i
tidn
nhau
m6t c6ch li6n
tuc
-+
C

sai
-r
Chgn
C.
D.
MOt
<tdn
ph6ng
ttiQn
chria
khf iodng n6n c6
5p su6t
thAp, khi
phdt
s6ng
sd
phrlt
ra
quang
ph6
vach phrlt
x4
-+
D tiling.
.Sa,*t6,v,
v^f;J\&t't-,