CHltawe
1:
DAD
nOWB
CB
m VJT It n -
TtM
TAT
Lt THUYfT VA
BAl
TAP
TRAC
MHlgM
-
Ti
Cau
23:
v = STT COS (nt +
-»
X
=
5
sin
(nt + ^)
^ '^os
(^^
^)
Cau
25:
= ^ = 8
cm;

1
^
A 2
=>
(p
= -
,
sin(p
> 0 ^
Cau
32:
;K:O =
4 cos
=
2V3
cm;
V
-
-4071 sin
=
-2071
cm/s
< 0
Cau
33:
a = -oi^x -^x = 3cm; x =
^4cos? =»
i4
=
2V3

2 m/s
Cau
37:
r = ^ =
0,5s
cj = 4n;A = ^ =
5cm;(p
= +|
A:
= 5
cos
^47rt
+ ^) =
-5sin(47Tt)
cm
Cau
38:
A
=
4cm, (o
=
^=10^,
m
s
56
tfAT
LY 12 - TOH TAT lY
THBYgT
VA BAl TAP TRAC
WBHlgM

47r
rad/s;A
=
20cm;
n
/ n\
(p
= + ^
X
=
20cos\4nt
+
-1
cm
Cau
41:
y4
=
4cm;
w = — =
7r
—;
w =—-
T
s ' ^ 2
X
=
A
cos
cm

B B
A
B B
C
A
A
51
52
53
54
55
56
57
58
59
60
B
C
B
D
B
A A
D
B
C
A:
=
4 cos
(20t-f)
sinq)

T = Is
57
CIHMRG1:DMB(IIGCI(HQC
WAT
It«
-
JtU
TAT IY
THBTfT
WA
BAl
TAP THAC
•BHICM-TAPI
Cau 46: Chieu dai 16
xo
ti
I5
nghich voi dp cung, cat
bat
16
xo
mpt
nura =^ do cung tSng gdp doi => chu ki giam
^/2.
Cau 47:
r'
- r =
27r
(Jf - Jf) =
0,083s

P
1712
=
SO^f
Cau53:w=
1^=
10 rad/s A^
=^
+
^-^
A
= 4cm
Cau 54:
T^~m
-»
m
=
mj
+
rriz
=>
= + r| -»
T
=
I5
Cau 55:
At
= 7 = Is
4
Cau 56:

Cau 60:
x =
2cm;
v <0 -*t
=
^
=
l s
6
3
VAT
It« - Tin TAT It
THBYfT
VA BAI TAP TRAC
IRHI|M
- TjP 1
CHa0N61:BABB9NGCtfl
61 62 63 64 65 66 67 68 69 70
C A
D
C
B
A
D
C A A
71 72 73 74 75 76 77 78 79 80
C
D
B
A

trong mpt chu ki c6 hai Ian vat di qua
vi
trf x = 2cm.
Cau 62:
=
Wt =^
\x\ ^-^
A
=
6cm;
max
= 10 rad/s ->
7 =
0,628
s
Cau63:a>= /^=107r —;
yjm
s
A^=x^
+
A
=
6cm;
XQ
=
3cm
= -;
T
A
At

CHlAfNG l:DA00QNGCdH9C
tfAT
lY
12
-
TUM TAT
LY THUYgj
VA BAI TAP TBAC NGHIEM
- TiJP 1
Cau
66:
- = 0,05s 7 = 0,25 w = 10n~
4 S
,2 _
Cau 67:
Cau 68:
k
= mo)^ = 50 N/m
A/
= ^ = 0,05m; F^^ = 100(0,05 - 0,03) = 2N
20
Cau
69:
A = 3cm = 0,03m; T = — = 2n^
9
Cau 70;
Cau 72;
^,
^^n(7na;«:) k(M + A)
M

2A
= 8cm=^A =
0,04m,
W =
\moP-A^
= 0,008/
81 82 83 84 85
86 87 88 89
90
D A D D
B
A
B B B
D
91 92
93 94
95 96
97
98
99 100
D
D
A C D A A A
C B
Cau
81:
Wt
= W-W^ =
\m{vlax
- v^) =

W = ^kA^ = \m.v^ax k = 125 N/m vam = 0,2kg
Cau
90:
=
M^t->
^ =
±
^ = ±5cm
Cau
93:
T^~l -*
I
= - =^ = - Ti =^ T = 0,6s
Cau94:/2~i-^/
=
/i
+
/2=>5^
=± + j-^=^f = 4,BHz
Cau
95:
r = —
2rr^
-
= 1,6s
9
Cau
96:
J = = 2,23s
Ti

^r-^

= — -»/ = 151,1cm
9
40
101 102
103
104
105
106 107
108
109
110
B
A
A
B
B
C
C A
C
B
111 112 113
114
115
116
117
118 119
120
A A B

20V3
cm/s
Cau 104:
2A = Acm =^A = 2cm - = 0,75 s
4
CfiulOS:
g' =g + a = g+^ = ^
T
9
3
X
2
5''
Cfiu 106:
F = qE/'y/g^g' = g-a = g-
l
\ct\E
m
r
= 271
5
7
= 1,29s
Cau
107:
F =
qE/'/'g^g'
= g + a = g +
\q\E
m

-
TAf 1
CHlfini61:B*B0tll6CtfH9C
Cau 112:
A(p
=^ yA
=
yjAl
+ Aj = 5cm
Cau 113:
A =
yjAl
+
A^
+
2i4i>42COS
(<P2 - (Pi) = 9cm
Cau 114: Dap an
A
vd B
sS
khong chpn vi dao dpng
2
cung pha vol
dao dpng 1, khong thoa phucmg trinh dao dpng tong hgp. Neu chgn
C thi
khong thoa pha ban dau cua dao dgng tong
hgp.
Dap dn D la phu hgp vi khi
hai dao dong ngu(/c

acos(6)t
+
q))
• Song ngang: Song c6 phtromg dao dong vuong gdc vai phuomg
truyin song.
• Song
dQc:
Song c6 phuong dao dong trung voi phuomg truygn
song.
Song
CO
khong truyen duac trong chan khong.
Khi song truyen tir moi truong nay sang moi truomg
khdc,
tan so
song khong doL
• Bir6'c s6ng(A):
- QuSng duong song truyen dugc trong mpt chu ki.
- Khoang each ngdn nhdt giiia 2 diem tren phuomg truyen
song ma dao dgng ciingpha.
X
=
vT
= J
Trong
do:
A: Buac song (m)
v: Toe do truyen song
Bai
tap mau;

tfA
BAI TAP
TBAC
llfiHIgM
-
TAP
1
CNIfdRG
2:
SdNG
Cd
Giai:
u =
2cos(1607rt),Vi
=
330 m/s,
=
1452 m/s
a.
a
= 2cm, T
= =
0,0125s, f =
i
= 80Hz
b.
=
VjT
=
330

Bai tap
1:
Can 1: (De thi tot nghiep nam 2007). Phdt bieu n^o sau day
\h
dung khi
noi ve song ca hpc?
A. Song am truyen dugc trong chan khong.
B.
S6ng dpc 1^ song eo phuomg dao dpng vuong g6e voi phuomg
truygn song.
C.
Song dpc la song eo phuong dao dpng trung vdi phuong truyen song.
D.
Song ngang la song c6 phuomg dao dpng trung voi phuomg truySn
song.
Can 2: (De thi tot nghifp nam 2008). Khi noi ve song ca hpc, phat bieu
nao sau day la sai ?
A. Song ca hpc la
svr
Ian truySn dao dpng ca hpc trong moi truong vat
chat.
B.
Song ca hpc truyen dupe trong tat
ck
cdc moi trudng
rSn,
16ng,
khi
va chan khong.
C. S6ng am truyen trong khong khi

NGHlf
M
- TilF 1
Cau 4: Goi A
la
buac song cua mpt song ca. Khoang each giua hai diem
gan nhat tren phirorng truyen song dao dong eiing pha bang
A. A/4.
B. A. C.
A
/2. D.
2
A.
Cau 5: Mpt son^
am
Ian truySn trong khong khi voi van toe 350m/s,
eo
buac song 7m. Tan so song la
A. 5000Hz. B. 2000Hz. C. 50Hz. D. 500Hz.
Cau 6: Mot diem
A
tren mat nuac dao dpng voi tan s6 lOOHz. Tren mat
nuac nguai ta do duge khoang each giua 7 gem 16i lien
tikp
la 3cm. Khi do
van toe truyln song tren mat nuac la
A. 50em/s. B. 50m/s. C. 5 cm/s. D. 0,5cm/s.
Cau
7:
Mpt nguai quan sat song tren mat h6

nuac voi van t6c ISn lugrt la 330 m/s va 1452 m/s. Khi song am do truyen
tvr
khong khi vao nuac thi buac song cua no se
A. giam 4,4 Ian. B.giam41an. C. tang 4,4 Ian. D. tang 4 Ian.
Cau 10: (De
thi dai hqc
nam 2007) Mpt nguon phdt song dao dpng
theo phuang trinh
u =
acos(207tt) (cm)
vdi t
tinh bang giay. Trong
khoang thai gian
2 s,
song n^y truyen
di
duge quSng duomg bang bao
nhieu ihn buac s6ng
A. 20.
B.40. C.
10.
D.30.
68
yAT LY 12 - TiM TAT L»
THUYgT
tf
A BAI TAP
TRAC
HBHIfM - TAP 1
CHlfdHIB

+ k2n
(2 dilm
gin
nhau nhat tren phuang truyen song
dao
dong
ngucc pha: A(p
=
TT)
- Vuong pha: A(p
= | + kn
(2 diem
gan
nhau nhit tren phuang truyen song
dao
dong
vuorjg pha:
A(p
~ ^)
X
la
khoang cdcx giua hai diim cdn tinh
do
l?ch pha
(x vdX
cung
don
vi)
• Phu-ong trinh truyen s6ng
Song i,

SAMG
ca
»iT
li
n
-
TiM
TAT
tt
TWYfT
VA lAi
ikr
THAC
•emCM-TAPi
Bai
tap mau;
BM
1: Nguon song O dao dpng
voi
phuang
trinh
uo = 5cos(57rt) (cm) tao ra
song Ian truyen voi toe dp 24cm/s va gia su trong qua
trinh
truyen song bien
do song khong doi.
a.
Tfnh
dp lech pha cua mot diSm M tren phuomg truyen s6ng ngu6n
O

= =
ZTT-^
=
A,
9,6 3
h.x =
OQ-OP
= 3,6 - 2,4 = 1,2cm:
A(p
= ^ = J
c.
X
= OP = 3,6cm:
UQ
= 5 cos
(STA
- ^) = 5 cos ^5ut - ~j
Bai
2: Song ca truyen trong mpt moi tnrang dpc theo tryc Ox voi
phuang
trinh
U=cos(20t-4x) (cm) (x
tinh
bSng met, t
tinh
bSng
giay).
Tinh
van toe truyen song.
Giai;

truomg
dan
hoi.
B.
Qua
trinh
truyen song \k qud
trinh
truyen nSng lupng.
C.
Qud
trinh
truyen s6ng la qua
trinh
truyen pha dao dpng,
D.
Qud
trinh
truyen s6ng la qua
trinh truyln
c&c
phSn
tii
v§t chat.
VAT
li n - HM
TAT
it
TmiYgT
wA

tinh
chit
cua song tai M la:
A.
M dao dpng nguprc pha
voi
O. '
3;r
B.
M dao dpng cham pha hom O la ~.
-hit
C. M dao dpng nhanh pha han O la .
D.
M dao dpng cung pha vai O.
Cau 4: Mpt song c6 tan so 500Hz, t6c dp Ian truySn 300m/s. Hai
dilm
gan
nhau nhat tren phuang truyen song phai
each
nhau gan nhat mpt khoang bao
nhieu
de
giiia
chung c6 dp lech pha bang y
rad
?
A.
0,1 m. B. 0,1 cm. C. 10 m. D.
1
cm.

pha voi ngu6n. Buac song truySn tren day la:
A.
160cm. B. 1,6cm. C. 16cm. D. 100cm
R3
mm 2:
sdNG
cd
VATLY
12-TI>MTAT
LY
THUYfT
VA BAI TAP
TRAC
HBHIEM-TAPI
Cau
8: (De thi dai hoc nam 2011) Mpt song
hinh
sin
truygn
theo phuomg
Ox
tu nguon O vai tan s6 20 Hz, c6 toe dp trayen song nkm
trong
khoang tu
0,7 m/s den 1 m/s. Goi A va B la hai
diem
nam tren Ox, a cung mgt phia so
voi
O va each nhau 10 cm. Hai phan tu moi truong tai A va B
luon

B.
UM = 5 mm.
D.
UM = 2,5 cm.
Cau
10: Mot song ca hoc Ian truyen
trong
mot moi truong vat chat tai mpt
2;r
cm.
diem
each nguon x (m) c6 phuang
trinh
song
w
= 4cos
Van
toe truyen song
trong
moi truong do c6 gia tri
A.
2m/s. B. Im/s. C. 0,5m/s. D. 3m/s.
Cau
11: (De thi tot nghi^p nam 2009) Mpt song ngang
truyin
theo
chilu
duong
trye Ox, c6 phuang
trinh

dp truyen cua song nay la
A.
100 cm/s. B. 150 cm/s.
C.
200 cm/s. D. 50 cm/s.
Cau
13: (De thi cao dkng nam 2008) Song ca c6 tan so 80 Hz Ian
truySn
trong
mpt moi truong voi van toe 4 m/s. Dao dpng cua cac phkn tu vat chat
tai
hai
diem
tren mpt phuong
truySn
song each nguon song nhiJng doan Ian
lupt
31 cm va 33,5 cm, l?eh pha nhau goe
A.
— rad.
2
B.
71
rad.
C.
2n rad.
D.
- rad.
3
VAT lY

trinh
song tai
dilm
M each O mpt doan 2,4cm la:
A.
Uj^
= 5cos
2
C. = 5cos
{cm).
{cm).
B.
Uf^, - cos
4
{cm).
D.
= 5cos
4y
{cm).
Cau
15. Tao song ngang tren mpt day dan hoi Ox. Mpt
diem
M each
ngu6n
phat song O mpt khoang 50 cm c6 phuang
trinh
dao dpng
UM
=
2eos[7r(t

r
•
Giao
thoa la su t6ng hop cua hai (hay nhieu) song ket hop
trong
khong
gian,
trong
do eo nhung cho c6
dinh
ma bien dp song dupe
tang
cuong
hoac
bi
giam
bat (hay
tri?t
tieu).
Dilu
kien
giao thoa
(dieu
ki?n
hai ngu6n kit hop): Hai song phai
xuSt
phat tir hai nguon
ciing
tan so,
cung

d^-d,=kX
+
Hi$u
duang
di
bang
so
nguyen
Idn
buac
song,
•y
Vf tri cue dgi
bac
n itng vai
k
= n
(v&i
n
= 0; ±
1;
± 2 )
• V| tri c^c
diem
dao d^ng vol
bien
d? eye
tieu:
(ggfn 16m)
d,-d,=

anh giao thoa:
-
6
vi
tri
duang trung true eua Si va S2 luon la day e\re dai.
- Ve
2
phia cua duang trung true la nhirng day euc dai va cue
tieu
xen ke nhau
hinh
dang Hyperbol.
- S6 cue dai tren doan S1S2:
SiS^
<kX< S^S.
- S6cvrctieutrendoanSiS2:
>A:= ?
SS
gid tri cua
k
Id
so
cue dgi hay euc tiiu
tren
doan
S1S2.
- Khoang
each
giua hai c\rc dai lien tiep bang khoang

VA
BAI
TAP TBAC
NBHIgM - TAP
1
CHirifRG
I:
SlNG
Ctf
Bai
tap mau;
6
mat
nuac,
c6
hai ngu6n k6t hop A,
B
dao dong
theo
phuomg
thang dung
vai
phuomg
trinh
u^=Ug^20co^{\Qnt){mm).
AB
=
26em
va
t6e

Giai;
=
UB
=
20
cos(207it)
(mm); AB
=
26cm;
v =
50cm/s
Buac
song: X
= vT = v— - SQ— =
10cm
a.
di
= ^2 =>
A
=
2a|cos7r(^2^)|
= 2a =
40mm
b.
di =
21cm;
dz =
26cm
=>
A

hinh
vuong
=>
CA
=
26V2
vd CB
=
26cm
Xet
CA-CB
26V2-26
=
1,076
A
10
=» diSm
C
nam giua
cue
dai
bae
1
va bac
2.
Do do, s6 c\rc
dai
gifta C va duang trung trye
eua AB la 1, nen:
-

goc
voi
mat
nuac,
c6
cung phuomg
trinh
u
=
Acoscot. Trong mien
gap
nhau cua hai song, nhung diem
ma
a
do cac
phan tu
nuac
dao dong voi bien dp cue dai
se
c6 hi?u duang di cua song tu
hai
nguon den do bang
A.
mot s6 le
\hn
nua
buac
song.
B.
mgt s6 nguyen Ian

Cac
diem thuoc
mat
nuac
va
nam tren duang trung true cua doan S1S2
se
A.
dao dpng vai bien dp bang nua bien dp cue dai.
B.
dao dpng vai bien dp cue tieu.
C.
dao dpng vai bien dp cue dai.
D.
khong dao dpng.
Cau
3: T^i hai diem A va B tren mat
nuac
c6
2
ngu6n song giong nhau
voi
bien
dp
a,
buac
song
la
10cm.
Diem

trinh
u
=
acos(1007rt) (cm),
van
toe truyen song
v =
0,6m/s. Xet 1
dilm
M c6 hi?u duang di
MA
-
MB
=
3cm.
Tinh
tir
duang trung
tryrc
cua
AB,
dilm
M nam tren
A.
Cue tieu bac 3. B. Cue dai bac
2.
C.
C\rc
tilu
bac 2. D. Cue dai bac

30 mm. D. 20 mm.
7A
yAT
It
1Z
-
TiM TAT
lY THUYfT
VA
BAI
TAP
THAC
II8H|£M
-
TAP
1
CHlTKNG
Z:
SdNG
Cd
I
Cau
6:
Trong thi nghi?m
tao
van giao thoa song tren
mat
nuac,
nguai
ta

tich
cua
cac diem dung yen. Khoang
each
gitta dinh cua hai hypebol ngoai cung
la
22cm.
Toe dp truyen song la
A.
70em/s. B. 80cm/s.
C.
7cm/s. D. 8cm/s.
Cau
8:
(De thi cao dang nSm 2008) Tai hai
diim
M
va
N
trong mot moi
truang truyen song
c6 hai
ngu6n song
ket
hpp cung phuang
va
cung
pha
dao dpng.
Bih

gom
2
nguon ket hop iS",,
S2 dao dpng cung pha, cung tin
so
20 Hz. Tai diem M (MSi
=
25 cm, MS2
=
20,5 cm) song
c6
bien dp c\rc dai. Giua M va duang trung tr\rc cua S,
S
2
con
CO
2
cue dai khac. Toe dp truyen song c6 gia
tri
A.
30 cm/s. B. 3 cm/s.
C.
45 cm/s. D. 45 m/s.
Cau
10: Trong thi nghiem giao thoa song tren mat nu6c, hai ngu6n
kk
hgp
A,
B dao dpng vai tin so 20 Hz, cung pha, tai mpt diem M
each

dpng dieu
hoa
theo phuang
thang dung
c6
tin
s6
15 Hz va
luon
dao
dpng d6ng
pha.
BiSt
wan
toe
truygn
song tren
mat
nuac
la 30
cm/s,
coi
bien
dp
song khong
d6i khi
truyen
di.
S6
dilm

dpng
voi bien
dO
cvre
dai
nSm tren doan thSng AB la
A. 9 em. B. 12em.
C.6cm.
D.
3
cm.
Cau 13: (De thi d^i hffc nSm 2009) hai diem A va B each nhau lOem
tren mSt chat long c6 hai ngu6n phat dao
dpng
theo phuong thing diing v6i
cac phuomg trinh la
UA
=
0,5sin(507rt)
cm
;
UB
=
0,5sin(507rt
+ n) cm, v§n t6c
truyen song tren mSt chit long Ik 0,5m/s. Xac dinh s6 diem c6 bien
dp
dao
dOng cure
dai tren doan thSng AB.

3
diem.
Cau
15:
(De thi dai
hQc
nSm 2010) 6
mat
thoang cua
mpt
chat long c6 hai
nguon song ket hgp A va B each nhau 20cm, dao
dpng
theo phuomg thing
dung voi phuong trinh
UA
= 2cos(407rt) va
UB
= 2cos(407it +
7t)
(UA
vd
UB
tinh
bing
mm, t tinh
bing
s). Biet t6c
dp
truyen song tren mat chat long la

I J
VAT
It K
-
Till
TAT
li
TIWTfT
VA
BAI
TjP
T«Ac
BGHItM
-
TJP1
CHIMMG
Z:
StNG
Cll
Khoang each giila nut va
bving
lien
tiSp
= —.
Khoang th6i gian giOra hai Ian lien tiep spi day duoi thing la
T/2
Song dung tren sgi day v6i hai
d4u
1^
2 nut

hoi M la nut song hay
b\mgs6ng.
c. Thay doi tin
so
dao dpng or A den gia trj 50Hz tren day van c6
song
dimg,
hoi tren
AB c6
bao nhieu nut song.
Giai:AB = 2m.
. 5 nut
^
4 bung n = 4:1 = 4^
=> X
= Im. v = Xf = 1.100 =
a
lOOm/s
b.
=
2£5
= 1^5
M
\k byng s6ng thii
2
ke tu A.
X/2
1/2
c.
X

n). B.
U2
=
acos(2nft).
C.
U2
=
—asin(2nft). D.
U2
=
asin(2nft).
Cau
2: Sgi day dan hoi AB
c6
chieu dai
/
voi dau
B c6
dinh.
Dau
A
dugc
rung
vai tan
so f
tao mot song toi tai
B
co phuong
trinh
=

sgi
day dan
hoi hai
dau
co
dinh
la
A.
Buac song gap doi chieu dai day.
B.
Buac song bang so ban nguyen Ian chieu dai day.
C.
Chieu dai day bang so nguyen Ian
VA
buac
song
.
D.
Chieu dai day bang so nguyen Ian nua
buac
song.
Cau
4: (De thi
tot
nghi^p nam 2007) Khi
c6
song dung tren mpt sgi
day
dan
hoi thi

diem
gan nhat ma day
duoi
thang la 0,2
s,
khoang each
giira
2 cho
luon
dung yen ke nhau la 10
cm.
Toe do truyen song tren day la:
A.25cm/s.
B.lOOcm/s.
C.20
cm/s. D.50 cm/s.
Cau
6: Tren mgt S(?i
day co
chieu dai
/, hai dau co
djnh,
dang
co
song
dung.
Tren day
c6
mgt bung song.
Biet

hai Ian
lien
tiep
sgi day
duoi
thing
la
A
V „ nv • ^ ^ ^ ^
A.—.
B.—. C. . D.
n£
£ 2nv nv
71
J
LY 12 -
TdM TAT
lY THUYfT VA
BAI
TAP TRAC
NEHlgM-TAP
1
CHIfdNB
2:
SONG
Cd
Cau
8: (De
thi cao
dang nam 2010) Mpt

9: Mgt sgi day dan hoi dai 60 cm rung vai tan
so 50
Hz tren day
tao
thanh
song dung
6n
dinh
vai
4
bung song, hai
dau la 2
nut song. Van
t6c
song tren day la
'
A.
12 cm/s.
B. "60
cm/s.
C.
75 cm/s. D. 15 m/s.
Cau
10: Tren mgt sgi day dan hoi dai 1,8m, hai dau co
dinh,
dang
co
song
dimg
vai

ngudi
ta
quan
sat
thay
ngoai
hai dau day co
dinh
con co hai
diem
khac tren
day
khong
dao
dpng.
Biet
khoang
thai
gian
giiia
hai Ian
lien
tiep vai
sgi day
duoi
thang
la
0,05
s.
Van toe truyen song tren day la

v^ 8
byng.
D. 5
mit
va 4
byng.
CSu
13: Mgt day
AB
hai diu c6
dinh
AB
=
50cm, v$n t6c truyen song tren
day
Im/s, tan
so
rung tren day
lOOHz.
Diem
M each
A
mpt doan 3,5cm
la
hay b\mg song thu may ke
tir
A:
A.
Nut song thu 8. B. Bung song thur
8.

Khi
d6 chiSu dai
%
va s6 nut s6ng trSn dSy 1^:
78
CHinMGKStlKCtf
Ul
It 1Z
-
TOM TAT U THBYfT V* BAI TAP
TRAC
MeHlgM
- TAP t
A.
/ = 62,5cm, 6 nut s6ng. B. / = 62,5cm, 5
niit
s6ng.
C.
/ = 68,75cm, 6 nut song. D. / = 68,75cm, 5 nut song.
Cau
15: (De thi dai hgc nam 2011) Mot sgi day dan hoi
cang
ngang, hai
dau
CO
dinh. Tren day c6
song
dung, t6c dp truyen
song
khong

voi
ngu6n am.
•
Am
nghe
dugc
c6 tan so tir 16Hz den
20.000Hz
va gay ra cam
giac
am trong tai con nguoi.
•
Ha
am:
Nhihig
song
ca hpc t3n s6
nho
horn
16Hz
ggi
1^
s6ng
ha
am, tai nguoi khong
nghe
dugc.
•
Sieu am:
Nhftng

•
Tin so
s6ng
am khong thay d6i khi truyen qua cdc moi
trudng khdc nhau.
Cvtimg
dO
am (I) t^ mgt diem
1^
d^i
lugng do bSng lugn^ nSng
lugng
ma
song
am tai qua mgt don
vj
dien
tich
d5t
t^i
diem do,
vuong goc v6i phuong truyen
s6ng
trong mgt don vj
thdri
gian.
Don
v}
cuong dg am la W/m^. Cuong dg am ti 1? nghjch voi
binh

sanh
dg to cua am
nghe
dugc
c6 cuong do I voi dg to cua am
chuan
c6 cuong do
IQ.
1(^5) = 10
Ig—
IB
=
lOdB.
DQ
cao cua am: Ph\ thugc vao tan so cua am. Am cao
(hoac
thanh) c6 tSn so
Ion,
am
thap
(hoSc
trSm) c6 tan so nho.
Do to ciua am: Gin
lien
voi
die trung vat ly
miic
cuong dg am.
Am
sac: Giup ta phan bi?t am do cac nguon

B.
tan so thay
doi,
con
buoc
song
khong thay doi.
C.
tan so khong thay
doi,
con
buoc
song
thay d6i.
D.
tan so va
buoc
song
deu khong thay d6i.
Cau
2: Lugng
nang
lugng
dugc
song
am truyen trong mgt don vj
thoi
gian
qua mgt don
vi

phat
ra la
A.
am ma
tai
nguoi
nghe
dugc. B. sieu am.
C.
h? am. D.
nhac
am.
Cau
4:
Di§u
nao sau day sai
khi
noi
vh
dac trung cua cua am ?
A.
Dg cao cua am phy thugc vdo tin s6 cua am.
B.
Dg to cua am
ph\
thugc vao bien dg hay muc cuong dg am.
CHIfdNG
2:
SONG
Cd

C.
Song am truyen dugc trong mpi moi truong vat chat dan hoi ke
ca chan khong.
D.
Toe do truyen am trong chat r3n thuong Ion hon trong chat long
va trong chat khi.
Cau 6: Khi noi ve song am, phdt bilu n^o sau day la sai?
A. Toe do truyin song am trong khong khi nho hom t6c dp truyen
song am trong nuac.
B.
Song am truyen dugc trong cac moi tnrong rSn, long va khi.
C.
Song am trong khong khi la song dpc.
D.
Song am trong khong khi la song ngang
Cau 7: (De thi tot nghi?p nam 2010) Khi n6i
\h
sieu am, phat bieu nao
sau day sai?
A. Sieu am c6 the truyen dugc trong chit rin.
B.
Sieu am c6 tan so Ion hem 20 kHz.
C.
Sieu am c6 the truyen dugc trong chan khong.
D.
Sieu am c6 the bi phan xa khi gap vat can.
Cau 8: Vai lo la cuong dp am chuan,
11^
cuong dp am. Khi muc cuong dp
am L

-
TAP
1
CHIfdNG
2:
SDNG
Cd
CSu 10: Khi muc cuong
dp
am tang 20dB thi cu6fng
dp
am tang:
A.
2
Ian. B. 200 lin. C. 20 lin. D. 100 Ian.
CSu 11: Khi cuong
dp
am tang gap 1000 Ian
thi
muc cuong
dp
am tang
:
A. lOOdB. B.20dB. C.30dB. D. 50 dB.
CSu 12: Nguoi
ta
do dugc muc cuong dp am tai diem
A la
90 dB va tai
dilm B la 70

A
la 60 dB, tai B la 20 dB. Muc cuong dp am t^i trung diem M cua
doan AB
la
A.26dB.
B. 17dB. C.34dB. D.40dB.
Cau 15: Muc cuong dp am do nguon S gay ra tai diem M la L, khi cho
S
tiSn lai gin M mpt doan 62m thi miic cudng
dp
am tang them 7dB. Khoang
cdch la S den M c6 gia tri xap
xT
la:
A. 210m. B.209m C. 112m D. 42,9m.
CHIfKNG
2:
SANG
CK
V*T LY
1?
- TiM TAT lY THUYf T VA tAl
TAP TBAC MGHltM
-
TAP
1
BAI
TAP
TRAC
NGHIEM

thai gian.
C.
S\
Ian toa vat
chat
trong khong gian.
D.
Sir
Ian truyen bien
dp dao
dong
cua cac
phan
tu vat
chdt
theo
thai
gian
Cau
2: Bu6c
s6ng
X la:
A.
Quang
duang
song
truyen dugrc trong cac chu ki
khac
nhau.
B.

trinh
truyen cac phan tu vat
chat.
B.
Trong qud
trinh
truySn
song
vat
chat
dung yen tai cho.
C.
Qua
trinh
truyen
song
la thay d6i van t6c truyen song.
D.
Qua
trinh
truyen
s6ng
1^
qua
trinh
truyen pha cua dao dpng.
Cau
4: toe
truyln
song

B.
Phucmg truyen
song
va tan
so
song.
C.
Phuomg dao dpng va phucmg truyen song.
D.
Phuomg dao dpng v^ v§n toe truyen song.
VjT LY
12
- TiM TAT
1Y
THDYfl VA
BAI
TAP TBAC
MGHIgM
-
TAP
1
CHtfflHG
Z: SdHG Gfl
Cau
6: Chpn
phat
bieu dung:
A.
TSn
so

s6
song
trong mpi moi truong
dSu
khong
phu
thugc
vao
chu ki dao dong cua song.
Cau 7: Mot nguoi quan
sat mot
chiec
phao
tren
mat
bien thay
no nho len
cao
10
Ian trong 18s, khoang
each
giiJa
2
ngon
song
ke
nhau
la
2m. Van
toe

deu
nhau.Khoang
each
giiJa
4
ggm
song
lien
tiep
la
135cm.T6c dp truyen
song
tren mat
nuac
la
A.
60cm/s. B.45cm/s. C. 350cm/s. D.
360em/s.
Cau
9: Nguoi
ta
gay mot dao dpng
a
dau
O
mot day
cao su de
tao mpt
song
ngang

go truyen
qua
khong khi. Xac dinh van t6c truyen am trong
thep
duong
ray
cho van toe truyen am trong khong khi la 340m/s:
A.5294m/s. B. 5300km/h.
C.
175,6m/s.
D.
175,6km/h.
QUA
TRINH
TRUYEN
SONG
Cau
11: Cho mpt
song
ngang
c6 phuomg
trinh
song
la:
u
=
8cos
In
.0,1
50j

A.334m/s. B. lOOm/s. C.314m/s. D. 331m/s
Cau
13:
(De thi tot nghi^p nam 2009) Mot song ngang truySn theo chieu
ngang true Ox, eo phuong trinh song la: u = 6
cos(47rt
- 0,027rx) (u va x
tinh bang cm, t tinh bang s). Song nay eo buoe song la:
A. lOOem. B. 150em. C. 50em.
D.
200em.
Cau 14: Mot song truyen doc theo true x duge mo ta bai phuong trinh:
u = 2cos 2(4nt -
O.Snx
—
^ (cm) trong do x tinh bang met, t tinh
bang giay. Van toe truyen song la
A. 8 m/s.
B.4m/s.
C. 0,5m/s. D.4m/s.
Cau 15: Mot song ca hoc phat ra tir mot ngu6n O Ian truygn tren mat nuoc
van toe 2m/s. Ngudi ta thay hai diem M, N gin nhau nhdt tren mat nuoc
nam tren eung duong thing qua O vd each nhau 40em luon dao dong ngugc
pha nhau. Tan so song do la:
A.0,4Hz. B. l,5Hz. C. 2Hz.
D.
2,5Hz.
Cau 16: Mgt sgi day dan hoi, manh, rat dai, c6 dau O dao dong dieu hoa voi
tan so f theo phuong vuong goc voi sod day. Song tao thanh Ian truySn tren
day voi toe do Idiong doi v = 5m/s. De diem M each O mpt khoang bang 2

= 2cos(27it
+Tc)
em. D.
UM
=2eos27it em.
Cau 19: Song Ian truyen tu ngudn O doc theo 1 duong thing voi bien do
khong doi. CJ thai di^m t = 0, dilm O di qua vi tri can bang theo ehilu
duong. Mgt diem each ngu6n mgt khoang bang 1/4 buoe song c6 li do 5 cm
d thofi dilm bang 1/2 ehu
ki.
Bien dg cua song la
A. lOem.
B.sVJcm.
C.
5
yfl cm.
D.
5cm.
Cau
20:
Mgt song ca hge Ian truySn dgc theo mgt duong thang eo phuong
truyen song tai ngu6n O la:
Ug
= acos (a)t) (cm). Mgt diem M each ngu6n
bang 1/3 buoe song a thai dilm t = 1/2 chu ki c6 do dich chuyin
UM
= 2 em.
Bien do song A la
A.4em.
B.

I'
Cau
23:
Hai diem M, N eung nim tren mgt phuong truyen song each nhau
X/3.
Tai thai diSm
ti
eo
UM
= +3cm va
UN
= -3cm. Tinh bien dg song A?
A.A = 2V3cm.
B.A^SVScm.
||,
C. A = 3 cm. D. A = V6 em.
Cau
24:
Song ca c6 tin s6 40 Hz Ian truyen trong mgt moi truofng voi van
t6c 2 m/s. Hai dilm tren mgt phuong truyen song each nguon song nhiJng
doan Ian lugt 10 cm va 12,5 em, dao dgng
A. vuong pha.
B.
nguge pha.
C.
eimg pha.
D.
l?eh pha
—
rad.

Cau 26: (De thi dai hoc nam 2007) ^e khao sat giao thoa song ea, nguai ta
bo tri tren mat
nuac
nam ngang hai nguon ket hgrp Si va S2. Hai nguon nay
dao dong dieu hoa theo phuong thang dung,
ciing
pha. Xem bien do song
khong
lhay d6i trong qua
trinh
truyen song. Cac
dikm
thuoc mat
nuac
va
nam tren duong trung true eua doan S1S2 se
A.
dao dong vai bien do bang nua bien dp cue dai.
B.
dao dong vai bien do c\rc tieu.
C. dao dpng vai bien do cue dai.
D.
khong dao dong.
Cau 27: Trong hien tugng giao thoa eua hai song phat ra tu hai
ngu6n
dao
dong nguge pha,vai k la so nguyen va A la
buac
song, nhung diem trong
moi

C. di - d2 = X-^ neu 2 nguon dao dpng nguge pha nhau.
D.
di -
d2
= (k + 0,5) X , neu hai nguon dao dpng vuong pha pha nhau.
Cau 29: Tai hai diem A va B trong mot moi truong truyen song c6 hai
nguon song ket hgp, dao dpng eung phuong vai phuomg
trinh
ihn lugt la
u^
=
acoscot
va Ug = acos(cot +7t). Biet van toe va bien dp song do moi
88
MAT
LY 1? - TtM TAT lY
THUYfT
VA BAI TAP TBAC
HGHIgM
- TAP 1
CHIfdNB
2:
SdNG
Cd
ngu6n tao ra khong d6i trong qua
trinh
song truygn. Trong khoang giua A
va B
CO
giao thoa song do hai nguon tren gay ra.

c6 cung phuong
trinh
u =
Acos(cot).
Trong mien gap nhau cua hai song, nhijng diem ma a do cac phan
tijr
nuac
dao dpng vai bien dp c\rc dai sS c6 hi?u duong di eiia song tir hai
nguon den do bang
A.
mot so le Ian nua
buac
song.
B.
mot s6 nguyen Ian
buac
song.
C. mpt so nguyen Ian nua
buac
song,
D.
mpt so le Ian
buac
song,
Cau
32: Tai hai
dilm
A va B tren mat
nuac
c6 2 ngu6n song nguge pha,

^ 20em. Hoi nguon M
each
2 ngu6n Si va S2 cac khoang 50cm va 100cm se dao dpng vai bien dp
A.
0 B. V2cm C. cm
D.
2cm
2
89
CHIfdHG
Z: 50IIB Cd VAT lY « -
TlJM
TAT it
THBYgT
Mk
BAI TjP TRAC
MHlgH
- TAP 1
Cau 35: (De thi dai hoc nam 2009)
Dieu
ki?n
dk hai song ca khi gap nhau,
giao thoa dugc vai nhau la hai song phai xuat phat
tir
hai
ngu6n dao dong
A.
cung bien do va c6 hieu s6 pha khong doi theo thai gian.
B.
cung tan so, cung phuong.

bang mot so le Ian nira
buac
song.
C.
Hieu
duong di bing mot so nguyen ihn
buac
song.
D.
Hi$u
duong di bSng mpt so ban nguyen Ian
buac
song.
Cau 37:
Phat
bieu nao sau day la khong dung?
A.
Khi xay ra hien tugmg giao thoa song tren mat chat
long,
ton tai
cac diem dao dong vai bien dp cue dai.
B.
Khi xay ra hien tugng giao thoa song tren mat chat
long,
ton tai
cac
dilm
khong dao dong.
C.
Khi xay ra hien tucmg giao thoa song tren mat chat

Cau 39: Mpt sgd day cao su cang
thing
nim ngang c6 dhu A noi vai mot
ban rung c6 tan so f = 0,5Hz .Sau 2s dao dong truyen di dugc 10m, hoi tai
diem
M tren day
each
A mgt doan 5m c6 trang thai dao dpng so voi A la:
A.
Ngugc pha. B. Cung pha.
C.
L?chpha
—
rad.
D.
Lfchpha
—
rad.
VAT
LY 12 - TdM TAT lY
THPYgT
WA
BAI
TAP THAC
WSHIgM
- TAP 1
CHlAfNG
Z: SdllG I
Cau 40: (Cao ding 2007) Tren mat
nuac

nhilng
ggn song dang hyperbol, khoang
each
ngin
nhk giCra hai
ggn
loi
lien
tiep
la
2cm.
So ggn
loi
va lom
xuit
hien
giiia
hai
dilm
S1S2 la
A.8va9.
B.9val0. C. 14val5. D. 8va7.
Cau 42: 6 mat nuoc c6 hai nguon song co A va B
each
nhau 15 cm, dao
dong dieu hoa
ciing
tan so, cung pha theo phuong vuong goc vai mat nuoc.
Diem
M nam tren

duong
elfp
thupc mat nuoc nhan
A,
B lam
tieu
diem la
A.
20. B. 18. C.28. D. 14.
Cau 44: Tai hai diem tren mat nuoc, c6 hai ngu6n phat song A va B c6
phuong
trinh
u=acos(40Tct) (cm), van t6c
truyln
song la 50 cm/s, A va B
each
nhau 11cm. Gpi M la diem tren mat nuoc c6 MA =10 cm va
MB=5
jliCm.
So diem dao dpng c\rc dai tren do^
AM
la
A.
9. B. 7. C. 2. D. 6.
Cau 45: Tai hai
dilm
A, B tren mat nuoc c6 hai ngubn dao dpng cung pha
va
cung tan so f = 12Hz. Tai diem M
each

trinh:
u =
acos(100;rt)
(cm). Van toe tniyen
song
tren mat
nuac
la V = 40 cm/s. Xet
dilm
M
tren mat
nuae
eo
AM
= 9 cm va
BM
= 7 cm.
Hai
dao dong
tai
M
do hai
song
tir
A
va
B
truyen den
la
hai

t
tinh
bang
s). T6c do truySn
song
a
mat
chat
long la 50 em/s. Goi O la
trung diem eua
AB,
diem M
a
mat
chk
long nam tren
duang
trung true cua
AB
va gan O nhdt
sao
cho phSn tu
chat
long tai M dao dong cung pha vai
phan tu
chat
long tai O. Khoang
each
MO
la

tai.
C. Song phan xa c6 cung tin so vai
song
tai.
D.
Sir phan xa a dau c6 dinh lam doi ddu
phuang
trinh
song.
Cau
49:
Song dung
duac
hinh thanh bai:
A.
Sir giao thoa cua hai
song
ket hgrp
B.
S\ giao thoa cua mot
song
tai va mpt
song
phan xa cua no cung
truyen
theo
mot phuong.
C.
Sir t6ng
hgrp

phat
song
ngimg
dao dgng
con
cac
diem
tren day
van
dao dgng.
C.
tren day c6 cac diem dao dgng manh xen ke
voi
cac diem dung yen.
D.
tren day chi con
song
phdn x?, con
s6ng
tai bj
trigt
tieu.
WAT
LY
n
-
Tiw
TAT
li
mi€j

tan so f= 5 Hz, tren day c6
song
dimg on dinh vai 5 byng song. Van toe
truyen
song
tren day
bang
A.
0,4 m/s.
B.
2 m/s.
C.
0,5 m/s. D.
1
m/s.
Cau
53:
(De
thi
cao dSng nam
2009)
Tren mgt sgd day dan h6i dai 1,2 m,
hai dau
c6
dinh,
dang
c6
song
dung.
Bik

55:
Mgt day
AB
dai 100cm c6 diu B c6 dinh. Tai dau A th\rc hien mot
dao dgng dieu hoa c6 tan s6
f
=
40Hz. V$n toe truyen
song
tren day la v
=
20m/s. So diem nut, s6 diem b\mg tren day la bao
nhieu?
A.
3 nut, 4
bving.
B. 5 nut, 4 byng.
C.
6 nut, 4
b\ing.
D.
7 nut, 5 b\mg.
Cau
56:
Mgt sgi day dan hoi
AB
hai dau c6 djnh.
Khi
day rung voi tan s6
f

50Hz.
Cau
57:
V^n
t6c truyen
song
tren mgt sgd day la 40m/s.Hai dau day c6 dinh.
Khi
tin
so
song
tren day 200Hz, tren day hmh thanh
song
dung vai
10
bvmg
song.Tin so nao cho duod day
ciing
tao ra
song
dimg tren day:
A.90HZ.
B.70HZ.
C.60Hz.
D.
llOHz.
I
CHlflMG
t.
SdNG

dao dong voi f = lOOHz va xem nhu mot nut, t6c do truy6n song tren day la
40m/s,
bien dp dao dong la
1,5cm.
S6 b\mg va be rpng cua mpt biing song
la
A. 7 bung, 3cm. B. 6b\mg, 3cm.
C.
7bung,
1,5cm.
D. 6 b\ing, 6cm.
Cau
60:
Quan sat song dimg tren sgi day AB, dau A dao dpng diSu hoa theo
phuomg vuong goc voi soi day (coi A la
nut).
Voi dau B t\ do va tan so dao
dong cua dhu
A
la 22 Hz thi tren day c6 6 nut. NIU dau B c6 dinh va coi toe
do truyen song tren day nhu cu, de van c6 6 nut thi tan s6 dao dong cua diu
A phai bang
A. 25 Hz. B. 18Hz. C.20Hz. D. 23 Hz.
Cau
61:
S6ng dimg tren
mpt
sgi day dan hoi c6
bieu thuc:
M

A. nut s6ng thu
5.
B. bung s6ng thu 5.
C.
nut song thii
4.
D. b\mg song thu 4.
Cau
63:
(De thi dai hpc nSni 2011) Mgt sgi day dan hoi cang ngang, dang
CO
song dimg 6n dinh. Tren day, A la m^t diem niit, B la mgt diem b\mg gan
A nhat,
C
la
trung diem ciia AB, vai AB
=
10 cm. Biet khoang thai gian
ngSn nhdt giOa hai Ian m^ li dg dao dgng cua phan
tijr
tai B bing bien do dao
dgng cua phSn tu t^ Cl^ 0,2 s. T6C dg truyen s6ng tren day la
A. 0,25 m/s. B.
2
m/s. C. 0,5 m/s.
D.
1 m/s.
If
AT
LY 1Z

Cau
65:
Chgn cau dung. Am sSc
1^
dSc tinh sinh ly cua am dugc hinh thanh
dira tren dac tinh vat ly cua am la:
A. Bien
dg.
B. Tan so.
C.
Nang lugng am. D. D6 thj dao dgng am.
Cau
66:
Chgn cau dung. Dg cao cua am phu thugc vao:
A. Bien dg. B. Tan s6.
C.
Nang lugfng am. D. Van t6c truySn am
Cau
67:
Chgn cau dung. Dg to cua am ph\ thugc vao:
A. Tan so va bien dg am.
B.
Tan s6 am va miic cuang dg am.
C. Buac s6ng va nang lugmg am.
D.
V$n toe truyen am
Cau
68:
Am thanli truyen nhanh nhat trong moi truang nao sau day?
A. Khong khi. B.Nuac. C. Sat. D.Khihidro.

thep mong, mgt dkn
c6
dinh,
con
l^i
dugc kich thich
de
dao dgng v6i chu ki khong doi va bang
0,08 s. Ani do
Id
thep phat ra
Ik
A. Sieuam. B.Haam.
*
C.
Nhac am. D. Am ma tai nguai nghe dugc.
CHKdNG
2:
SdNG
CO
«AT
LV 12 -
T6M
TAT LY THUYft «A BAl
TAP
TRAC
IISHigM
-
TAP
1

the cam th\ duac song
ca
hoc nao sau day:
A. Song
CO
tan
s6
lOHz.
B.
Song c6 tan
s6
30kHz.
C.
Song
CO
chu ky 2 // s. D. Song c6 chu ky 2ms.
Cau
73:
(De thi cao
ding nSm 2010)
Khi noi ve
song
am,
phat bieu nao
sau day la sai?
A.
d
Cling
mpt
nhi?t

am
S mpt
doan
d.
Nguon nay
phat song cau. Khi nguoi do di
lai gin
ngu6n
am
50m thi thay cucmg dp
am
tang len
gdp
doi. Khoang each
d
la:
A.
«222m.
B.
«22,5m.
C. «
29,3m.
D.
«171m.
Cau
75:
Mpt nguon diSm O phat song
am
c6 cong suat khong doi trong
moi

Cau
76:
d
khoang each
di
= 1000m tnrac
mpt
ehigc
loa,
miic cuong
d
am
la Li=
lOdB. Tinh cucmg
dp
am
I2
tai
diem
nam
each
loa mpt
khoang
da
=
10m.
Bik
song do loa phat
ra
Ian toa trong khong gian dual dang soir.

am
S phat
ra
mot am c6 cong suit P khong doi, truySn ding
huong
\h
mpi phuomg. Tai dilm
A
each S mpt doan
rA
=
Im, muc cuong
dp
am la
70dB.
Gia su moi
truong khong
hap
thvi
am.
Mure cuong
dp am tai
diSm B each nguon mpt doan
TB
=
lOm la:
A. 30dB.
B.
90dB. C. 50dB. D. 60dB.
Cau

A. chu ki cua no tSng.
B.
tan
so cua no khong thay d6i.
C.
buoe song cua no giam.
D.
bu6e s6ng cua no khong thay doi.
Cau
80:
Khi noi v^ song am, phdt bilu nao sau day la sai?
A.
O
cimg
mpt
nhi?t
dp, toe dp
truyen song
am
trong khong
khi
nho
horn
t6e dp truySn s6ng am trong nuoc.
B.
Song am truyen dupe trong cac moi truong rSn, long va khi.
C.
Song am trong khong khi la song doe.
D.
Song am trong khong khi la song ngang.

=
50Hz
A.
I '
Can
6:
6A
=
3cm
A
=
0,5cm;
v
=
Xf
= 0,5.100
=
50cm/s
Cau
7:
A
=
2m; 57
=
8
r =
1,6s; v
= ^ =
^
=

^
=
i^
=
0,ls;^
=
-^
= -^ = 20
w
2071 ''AT- 0,1
BM tap
2; Qu^
trinh truyen song - 3$ l^ch pha - phirong
trinh
truyen s6ng
Cau 1 2 3 4 5 6 7 8 9 10
B^p dn D A B A B B C A
c
Cau 11 12 13 14 15
D^p ^n C C B C D
-
1 V 360 „ _ A
27rx 27r0,2
TT
^«"2:A
= -
=
-
=
0,8m;

LY 12 -
TIJM
TAT LY THUYET VA BAI TAP TRAC
HEHIgM
- TAP 1
CHI/lfNG2:
SdNGCd
n
2nx
0,6
=>
X -
0,1m
Cau 5:
A
= vr =
1.2
=
2m; A(p
= ^
TT
= ^
=>
;c
=
Im
Cau
6:
= —
=*

Cau 8: ^(p
=
2nx
n
+
kin =
2nfx
k=tl-l
V
2
.
Vi
0,7
< v < 1
kG2
nenl,5
<
fc
<
2,35
fc =
2 ->
v
=
80cm/s
Cau9:uM
=
5cos[7r(^-g
=
0

A —
=
200cm/s
2n
Cau
13:
A
=
7
=
^
=
5cm;
x =
33,5
-
31
=
2,5cm;
J
80
Inx
In.
2,5
=
n
Cau
14:
A
=

=
2
cos(7rt)
(cni)
CHI/dNG
Z: ^dNG Cd
VAT
LY
IZ-TfiMTAT
LY THUYfT VA
BAI TAP TRAC
MHlgM-TAPl
Bai
tap 3; Giao thoa
song
Cau
1
2
3
4
5
6
7
8
9 10
Dap
an
B
C
A A A

=
1,2cm;
6J
IOOTT
d2
-
di
3
3
~ " 1~9 ~ ^'^ ^
Cau
5:
A
= =
v—
=
80—
=
16cm;
A
= 2a|cos [%
(6.2
-
di\
]|
=
2.201
cos
[71
/29

4.20
=
80cm/s
Cau
8:
- =
1,5cm
A
=
3cm;
v
= Xf =
3.40
=
120cm/s
=
l,2m/s
Cau
9:
d2
-
di
=
3A
A
= =
1,5cm;
•5
i;
=

=>
-4,1
<
fc
<
4,1
—>
cd 9 gid
trf k 9CD
yAT
LY IZ -
TfiM
TAT LY THUYfT
VA BAl
TAP
TBAC
weHieni
- TAP 1
CHI/dNG
Z:
SUNG
Cd
Cau
12:
i = Y =
6cm
Cau
13: Hai nguon dao dong ngugc pha
Buac song: X
= vT = v—

ndm giua cue dai bgc 2 va
3
A
1,5
So cue dai tren doan
CD:
2.2
+ 1 = 5
(ke ca cue dai bae 0)
Cau
15: Hai nguon dao dpng
nguae
pha;
2n
In
X
= vT =
v—=30-—= 1,5cm
S6 cue dai tren doan
AB:
/
1\
-5iS2
<• k+-
A
<
5i52
\/
=>
-13,8

= 19
Bai
tap 4:
Cau
1
2
3
4
5
6
7 8 9
10
Dap
an
A
C
D
C
D
A
D
C
D
c
Cau
11
12
13
14
15

=
-acos(2nft)
Song phan xa tir B truyen den
A:
=
-acos(2nft
- ^)
Cau 5:
^
=
0,2
r =
0,4s; ^
=
10cm
A
=
20cm;
V
=
4
=
50
cm/s
Cau 6:1 hung song ->/
=
l.^
=
^=»/
=

15m/s
Cau 10:
6
fcwn^
sdn^- / =
6.^ ->
A
=
0,6 m; i?
=
A/
=
60m/5
Cau 11:4
nut
3 bung song
A
T
/
=
3 *
A
=
0,8 m;-
=
0,055 =>
7 =
0,1s
1;
=

Cau 14:
A
=
^
=
0,25m; /
=
(5
+
i) ^
=
62,5cm;
5
bo song 6 niit song
Cau 15:
/ = = 4^ = 6^ /2 =
63//z
VAT
1Y
12
- TiM
TAT
lY
THUYf
T
VA
BAl
TAP TBAC
NGHIIM
- TAP

10
Igf
/
=
IO^/Q
=
0,001
W/m
'0
Cau 10:
L2
-
Z-i
=
20dB 10 Ig^
=
20 => /z
=
lOO/i
Cau 11:
/, = 1000/1 =» L2 - ^1 =
10 Ig^
=
30dB
'1
Cau 12:
-
LB
=
10 Ig^ =>

dg
101
AM
= 2
'd
26dB
0
M
CHlTlMG
Z:
SANG
CK
V*T
lY
12
-
TIJM
TAT
lY THBYfT VA BAl
TAP
THAC
HGMlgM-TAPI
Cau 15:
L2 - = 10 \g'f = 10 Ig
(^f
=> 7 =
20
Ig
(Ji)
di

15 16 17
18 19 20
Dap
an
B B
A A
D
C A
B D
A
Cau
7: 97 = 18s =» T = 2s,X = 2m,v = ^= Im/s
Cau
8: T = =
0,75s,
3A =
135cm
80
=>
A =
45cm;
v = ^ =
60cm/s
Cau
9: V = ^ =
5
j;
A
=
177

a)t-
2nx\
,
TT ^ 1000
^
= = Hz -> t; = A/ =
lOOm/s
10
TT
Cau 13:
u = 6
cos(47rt
-
0,0027r;c) <->
u =
acos
(wt - ^)
->
A =
100cm
104
'^VjT lY
12
- TiM TAT LY THBYfT VA BAl TAP
TRAC
IGHieM - TAP 1
CHIflhlG2:Slill&Cir
Cau 14:
u =
2

A
Cau 16:
Acp
=/c27rd
= fcA = fc^/ = fc J
Voi
fc la s6
nguyen, ta chon
/ =
SOHz, khi
=
Cau 17:
Aa? = -— = —- = n + k2n => = — - -
^
A V w 2
98
< / < 102 => 2,93 < fc < 3,07 -> = 3 -> A = 4cm
Cau 18:
A = v7 =
t?—
=
20cm
27rx\
UM
= 2 cos
I
2nt - .
\ /
= 2
cos

'2717
2713^
7
2
a
= 4cm
Cau
21
22 23
24
25
26
27
28
29
30
Dap
an
B
B
A
B
A C
D
C
A
A
Cau
31
32