Tải bản đầy đủ (.doc) (20 trang)

ĐỀ THI THỬ ĐẠI HỌC (2014) MÔN VẬT LÍ KHỐI A & A1 - ĐỀ 508-2014 CÓ ĐÁP ÁN CHI TIẾT4

Bạn đang xem bản rút gọn của tài liệu. Xem và tải ngay bản đầy đủ của tài liệu tại đây (323.3 KB, 20 trang )





Thời gian làm bài : 90 phút
 !"

 
Cho: hằng số Plăng h = 6,625.10
-34
J.s, tốc độ ánh sáng trong chân không c = 3.10
8
m/s;
!"#
$% &'$( )
*
+
=
độ lớn điện tích nguyên tố e = 1,6.10
-19
C; số A-vô-ga-đrô N
A
= 6,023.10
23
mol
-1
.
#$#,  /-0%1 +23,++4+-56/'7839/ ++4+-56/':π;78
*
<=->7
 -?%3,+23,+$(7839@A/- /A/B39=->79/?C %-DE3,+2/ +


6/$(π;78
*
<
F:$:) G:$() :*: H::()
%!&!'37 IJKFJ';78< 7 IJK*FJ':L;78*<JMKJ$:LJMJ:*
NJ:3J$(78J37 I8*JMO-JO8PQ+R9@A/OJ'O8P

*
*
:
:
' '
* P * *
kx
kA A
x= ⇒ = ±

H@A/- /A/3,+%E> /"+0%ST/3UV -?%
I:J
'
*
A
#,W!:/2+XJYL8Z
=->7 J$(π;78*<J 7 I8*JMIJ[F8*JH M:3,+%E> / ?30#G3,W
->7!Q/3\=->7J'8PJ:$(;2+!:]!JL8*<G
#$#,^/V/+R_+R1I  /-0%1 3\`ST/Va
+ P
Z
x A t
π

π
 
= +
 ÷
 
=->7
+C->7-b% 3UV+2 /A/6/@A/R?*:$P39*:$(R?RScR9 %d
(.
$*:e&

Pf
).
$*:f(

Pf
.
$::e

$*
*.
$*:e&

*P
%!&!' +2>/g99E"*++S %
+,- .!&! /012.32'
h5J:a
:
:
'
'

:
A
x
v

=



<

ST/Q/
3\->7!
:
V31/V1
]
!
!
:
Y
F
O
A−
A
*:$'
*
M
x
:
M

*
*
A

*
*
A
*:$P
*
M
*:$(
*
M
*:$Z
*
M
hi
j j
d t
=
a
* *
$ $ *
j j j * *
* * *
d t t
A
w kA kx x= + = ⇒ = ⇒ = ±
H+2*  V/7.+%ikl+2PR? /A/6/@A/#a3,EW`ST/``/g31/
V1 l+R?-099R0i0BT2S/+ @+P;.+m P<3\7n+-+a7

+%ik  /-?%39RSc/S+1R539a7ig/=/ ST/Q/3\S%ES3,E
 R97S %
ho?Q*:$P l3@+9*:$*;3a*:$*R9+ @+PR0i039BT*:$P<->=
->7 /A/6/@A/R?Q*:$P-Sc+R9
*:$P *
*:$*
P
t T t= +
V/-2
*
R9ig/=/ ->
U++%E>V+%/!
:
!
*
 +2
: *
*
e
Z f *P
M M
T T T
t t

= = + =
#,E
*:$P
*:$* e $*:e& $*:e&
P *P *P Pf
T

t T s
T
= + = =
+,- .!&! /0-4. 5-6  7 '
h#UVW-2
*
O O 9
*
d t
l x A= = ±
H*3UV9E-IQ/ %b% #G +2>b% p79
9ER9a7=->7R?Q*:$P3,++#G7.ig/
*
*
L A=

h3\R?Q*:$Pa
*:$P
(:'
P
=
S* +2
*:$( *
(:'t t T= +
"a3la
Hq9/+2
* *:$P
e e $*:e& $*:e&
(:'
Z f *P *P *P Pf

T T T T
t t T T s= + = ⇒ = + = =
#$8 +C->7  /-0%9V Vn+  ]I39]E3%r//2+3\ %;]R93UV+?6/+m +g
 +C->7<G@`ST/Va  /+m  +C->7R9IJ*+;(LhL8*<+739EJP+;(LsL8Z<+7N
+C->7QC+2R IJ
'

+739- /-"+0%D7aig/++/t  +C->7R9
(+
' '
+7 )+
e
+7 +
* '
+7 *+
$(
+7
%!&!'
9' IJ:3
I
u:+C->7b% #G"+0%D7
EJ
* '
3
E
M:+C->7E-v
* '
V 
wN+C->7I-v#G-@3UV
':

= −
@=/ 8Z
wV/=/ 8Z-2+C->7E-v
* ';
=
V ST/
Vx30R5-y/
* ';
=
w#UV+m *3,Sa3l
Ng/++/t *3,R9
( ) ( )
* *
' * ' $(<
= + =
+7
 =*
;R?'<
;R?*<
;R?$<
A−
O
A
x
*
*
A
*
*
A


'
*
A
#$!.+R_+RIV"z/-Q/39$+R_+-T+-pb+2+{/iRSc/7iir/+2
-pVS=/+y/  /-0%1 3\+%ia
$
J
*
N-^+g*+R_+V/+{/-pVS=/-0%+2
3"++%/-pVS=/67/ /a /|+m +R_+R1IA/$PPR?+R_+-T  /3\
J(8Z%ia+m +R_+RIV/-pVS=/6/ %d
F$ G$* $PP G*
%!&!oy++S +2-pVS=/
$
J*π
m
k
J*π
g
l∆
;∆RR9 /|+m R1Ii3,W#G

*
J*π
g
l
;R 9+m +R_+-T<
 +2
$

J
*
JM∆RJR;w<
N+2-pVS=/R4++n/R3,}Jh~
-
JM/

J/h
N-2}
$
J*π
hd
g
l•∆
39J}
*
J*π
hd
g
l
JM
T
T
$

J
l
l•∆
J
l

l∆PP$
J$*
}
$
J$*J$*
Z
(
J$;<
#$" +R_+-T4+p  /-0%1 5+{/$-U ->7V7^-C;+{/iRSc/39+{/A/
RSc/<+RA+$+2+0%9R$J$739 /2+R9€
:$
+m +R_+*R9R*J$PP7€
:*
• /2++m +
R_+$8+R_+*R9
F:Z&G$PP$*H:f'
%!&!'A/RSc/+m +R_+-T-Sc+I+-U"+r/Q+
O
$
J7
$
/R
$
;$Y+α
:$
<J7
$
/R
$
*

*

:$
*
α
≈7
$
/R
$
*
:$
*
α
O
*
J7
*
/R
*
;$Y+α
:*
<J7
*
/R
*
*
*

:*
*

α
≈7
*
/R
*
*
:*
*
α
!9O
$
JO
*
397
$
J7
*

*
:$ :$
*
*
:* $ :*
$PP $*
l
l
α α
α α
= = ⇒ =
 =

#$>' ->7/!39  /-0%1 VVn+]I;/+]R93UV+D6/+m +y/<3\
`ST/VaR?RScR9I
$J
( +;P h 8*<+7)I
*
J$:+;P h 8'<+7Ng/+++4+-5/t  
->7/R9
F( +7Gf(+7(+7H$(e+7
( ) ( ) ( )
1 2 2 1
1 2
+ Chó ý víi bµi to¸n t×m kho¶ng c¸ch hay thêi gian gÆp nhau th× ta tÝnh hoÆc .
+ Quay l¹i bµi to¸n: 5cos 4 5
max x
x x x x x x
x x x t cm d A cm
π

∆ = − ∆ = −



∆ = − = ⇒ = =



#$?'!.+R_+R1IV"z/-Q/-?%S\+m R1IV"7.3,B+2iRSc/7v3UV+D
6/]i‚3,z/-Q/I%/S\-@3UVGVxgir/3,+ -?%!R97.3UV67
V]G=/ /_C->3,-vG-@!39v]-@!/C` R? %G@+ V%/a+m 
3,V++b%|/-S=/9E+Rp+ %Z:+78+ +4+-5+m 3,+2/VUIC`I•6/ 

%
FZ*f+78 GP:+78 *:+78 H$*(e+78
ƒn/-S=/V1FR9  -?%3,W3UVST/
#7 IJP:LJ$*(ZZ+78 =*
#$@'R_+R1I/x73,B+2iRSc/7J$::/R1I+2 +Q/i  /+S„/Q+S\+n/+m
/5R4+@%?9N?+m /5R4+R9f
$
J'…a †-U+m +R_+R9F
$
N?+m
/5R4+R9f
*
Je…a †-U+m +R_+R9F
*
JF
$
oCE`
*
J$:.+Q/+m R1I+2>R9
(+iJ*::;87< )+iJ*:;87< +iJ$::;87< *+iJ$:;87<
%!&!'G +./SW/lR9-•iA/vF
$
-@F

Vx/g7I%/F
*
?V/+m p67V/ig/v'… e…
ii/gV l67V/ig/'Z87-@$&Z87N+2>67V/`573VR9$::87
#$A5 ->7FGV7^+CRB/+2 /%x`2/  /-0%1 "`ST/Va
%

$
J%
*
J +;$::π<;77<FGJ$'+77.->7V7^+CRB/++->7G7.ig/GJ$'+739
c`3\FG7./2+$*:
:
+ V%E02/V7^+CRB/R9$78V+5F+2->7  /
3\ +4+-5R9
F$$ G$' & H$:
GS\+2/
cm
f
v
*
(:
$::
===
λ
‡‚->7 +2
eZP
*
$''$'
$*
=

=

=

λλ

CBCA
dd
‡‚->7F +2
(Z
*
$'::
$*
−=

=

=

λλ
AB
dd
#,E
eZP(Z ≤≤− k
!
F;G<
]$
!$
!*
]*
7; <
7; < 7; <
7; < 7; <
7; <
*
Z

8 P
$*
B M
B M O M
B M O M
B M
T
t
t t
t t T
T
t

− −
− −


=
= 

 

 
+ =



=




;*<
7 I
'
* 8 Z
8 *
Z
* 8$*
'
Z: 8
Z:*
P: 8
'
B M
M
O M
A A
V
T T
x A
A A
V
T T
A
cm s
T
v A cm s
π
ω π




= =


⇒ = ⇒


= =


⇒ =
⇒ = = =


F G
#$'VcDE+2 ->7!39i2/+S R V%E0aR9V%/->7+m -5!N
2/V%E0v!-@3\ ir/-†a39=->7
$
!39R9 ->7/? %C79++
`?ƒ5-2+2R ST/Q/R9YZ77hZ7739=->7i@@`/?C
*
J
$
h:e(aR +m
++`?ƒ5!39-0%R9h*(77+   /+m `?ƒ39`=->7
$
+2/VU/?-y/
C
(+P+78 )+*f+78 +$P+78 *+f+78

( )
( )
( ) ( ) ( )
( )
1
2 2
2
0
2 1
1
+ T¹i thêi ®iÓm dùa vµo h×nh ta cã: 12
+ T¹i thêi ®iÓm dùa vµo h×nh ta cã: 2,5 6 6,5
2
Tõ 0,75 3 / cung mµu xanh ë h×nh bªn ph¶i 90
4 3
T¹i thêi ®iÓm ®ang
t MP cm
t A ON OM mm
T
t t s T s rad s
t N
π
ω
=
= = = + =
+ − = = ⇒ = ⇒ =
+
( ) ( )
ë vÞ trÝ c©n b»ng nªn cã tèc ®é cùc ®¹i 13,6 / 1,4 /
N

N v A mm s cm s
ω








= = ≈

#$'2/v/V7.cDE-9xFG3\ -?%R9y2/+25/EJ*
L
P
I+*::π+7
V/-2I6/+76/>7/?FC  /3\ $+7++FR9
F$+7 G
P
'
+7 
*
'
+7 H*+7
#$8' +2
cmf
P
*
=→=
λ

π
λ
π
39
Hzf (:
*
$::
*
===
π
π
π
ω
G 2/v/5n/2/F
n/
J* J*+7
G +m 2/v/5->7!++y2/-5R9
daA
λ
π
*
*=
cmcmdddd
'
*
$*
f
Zf
*
Z


*
$
f
*

f
*
*$
77
==→=→==↔=
πππππ
B
A
B
M
N
P
M
N
P
hZYZ
2,5+
( )

1 2 1
0,75t t t s→ = +
u
v
#$' /%x2/

$
)
*
  /+%/` 39++ %f+7#07.` +m 
$

*
RCE7
 ->7
'
P +
'

P
JP+739c`9a /+D
$

*

'

P
G@S\+2/+m 2/
V7^S\+R9λJ$+7B-S=/+ +m a /R\CR9 %->V-5'P+2
(->7  /+4+-5
FZ+7 G'+7 '+7 HP+7
#$'
%!&!>V
'


P
+2(->7  /+4+-5
a5
'

P
R9  /+4+- Q 
Q+R9iJ[*

$
J
$

'
)
*
J
*

'

$
s
*
J*λJ*+7;w<

$
s
*
J*λJ*+7;w<


$
*
J
*
h
$

*
J
*
hZ
*

*
*
J
*
h
*

*
J
*
h*
*


$
*

s
*
J'*

;ww<
v;w<39;ww<%EV 
$
h
*
J$Z+7JM
$
J&+79 9
**
Z& −
98
(
-C+ =,D,
#$8' /%x`2/i@c`FG3\
$ZAB cm
=
V7^/+CRB/  /"`ST/
Va
( ;': < )
A
u c t mm
π
=
( ;': 8 *<
B
u c t mm

π π
= +
 2/ir/-†+ 2/
Z: 8 v cm s=
]R9
V%/->7+m FG->7-Q/EV-5FG/?]C39I ]C++]7.-5ST/Q/R9
(+$+7)f+7 )+:*(+7)ee(+7 +$+7)Z(+7 *+:(+7)e(+7
( ) ( )
( )
( ) ( )
1 2 2
+ Ta cã ®é lÖch pha gi÷a hai sãng göi tíi 1 ®iÓm bÊt k× lµ: . ,
2
+ NÕu thuéc cùc ®¹i th× 2 ,
+ NÕu thuéc cùc tiÓu th× 2 1 ,
+ §èi víi bµi nµy M, N thuéc cùc
∆ = − = ∆ − ∆ ∆ = −
∆ = ∈
∆ = + ∈
M
M
M
d d d víi
M k k Z
M k k Z
λ
ϕ ϕ ϕ ϕ ϕ
π
ϕ π
ϕ

( ) ( ) ( )
( ) ( )
( ) ( )
1 2
1 2
1 2
4
tiÓu nªn: 2 1 . 4 1,5
2 2
+ V× gÇn nhÊt nªn 0 2 1,5 5
+ V× M gÇn O nhÊt nªn 2 4 1,5 3,65 3 7,5







 

∆ = − = + + = +
 

 

= ⇒ ∆ = − = = ⇔ =


⇒ ∆ = − = = + < ⇔ < ⇒ = ⇒ =


d d d k k cm
M O k d d d OM cm OM cm
d d d ON k AB k k ON cm
π
π
π
A
B
B
M
N
#$'!5+-pI E+0%/x7o/‚`@`V/-2n-p+2-p%/ E-†-4T+VoJ:
^39 -?%-575+7.-p`I E+0%+2>%Q+%J*::+$::L;#<NJ$J$:
YP
8L;~<
39iJ*J$:
YP
8(L;~<a+S=/ 1/-pQ+=ST/Q/
$
39
*
-0%Rp+` 3\%7./2+R9
L8'o+2/VUR9
FJ$$((ˆ)oJ'8LGJ$((ˆ)oJ'8*LJ$$((ˆ)oJ$(8LHJ$$((ˆ)oJ*8L
#$'%!&!‰
$
J$::Ω)‰
*
J(‰
$

J(::Ω
N‰

J‰
$
a
$
+,7` T%/2+
'
π
 
'
π
J
R
ZZ
CL $

J
'
JM‰
o
s‰
$
J
'
;w<
N‰

J‰

*
a\7` T%/2+
'
π
 ;Y
'
π
<J
R
ZZ
CL *

JY
'
JM‰
o
s‰
*
JY
'
‰
o
s(‰
$
JY
'
;ww<
oCE;w<s;ww<JM*‰
$
J

'
JME9
'
*
$C
Z
9
'
*::
9"F?Ω9"F"Ω
JM‰
o
J‰
$
h
'
J'::ΩJMoJ
π
$::
L
Z
J
π
'
;<
%!&!
 +2‰+$J$::Š‰+*J(::Š
#9 L8'J‰
o$
8J‰

o*
8⇒‰
o$
J‰
o*
‰
o
s‰+
$
J‰+
*
s‰
o
⇒‰
o
J;‰+
$
h‰+
*
<8*J'::Š
⇒oJ'8L
;‰
o
s‰+
$
<8
'
J⇒J*::8
'
J$$((Š

#$"'^-p`I E+0%+2/VUp%n/ir/-†$(:#39-575+F!G/x7-5F!+•
+Q -pVW-575+!G+Q n-p+2-p%/7_+@`3\7.+%.+g7%?+2 4
+g7o E-†-Sc+G@ %i E-† 4+g7oa-p`p%n/ -?%75+!GA/*
*
R?
391/-pV/75+VS\+39 %i E-†Rp+`  %π8*a7-p`+4+-5/t  -?%75+
F!i+S  E-†od
(+$::# )+$::
'
# +$::
*
# *+*::#
( ) ( )
( )
( ) ( )
( )
( ) ( )
( )
( ) ( )
( ) ( )
( ) ( )
( )
( ) ( ) ( ) ( )
i 1 2
2 1
2
2 2 2 2
2 2
1 2
2 2 2 2 2

1 2 1 2
i 1 2 1 2
2 2
2 2 2 2 2 2 2 2 2
1 2 1 2 1 1
;
2
XÐt bµi to¸n tæng qu¸t nh sau:
.
Ta cã: ; cos cos 1 1
2 2

.
i
MB MB
R L C R MB
R R
i R R
R MB R MB R MB MB
U k U
U U U U U U
U U
U U U
U U
U U U U U U U k U U
π
ϕ ϕ
π π
ϕ ϕ ϕ ϕ ϕ ϕ


=



=

= + − = +
= ⇒ + = ⇒ + = ⇔ + = ⇔ = +
⇔ = + − ⇔ = ⇔ = ⇔
( )
( )
( ) ( ) ( )
( )
( )
( )
( )
( )
2
1
2
1
2
2
1
2 2 2 2
1 1 1 1
2
2
2 1
1

2
.
MÆc kh¸c ta cã: U
1
150.2 2
LiÒn, ngay vµ lËp tøc ¸p dông c«ng thøc trªn ta cã: 2 2 2 2 100 2
2 2 1
R
R
R MB R R
R
U
k
U
U k
U U U U
k
k
U U k U V




























=




= + = + ⇒ =

+




= ⇒ = ⇒ = =


+


#$>' +4++m 7.7E`-pI E+0%7.` 39 -?%-575+/9o@`
GBb% -pVWDE+vr/+4+-5/b% +++%.DE+m 7E`ir/-NVr+m 7E
`b% E3\+
$
J':31/8`y39
*
JP:31/8`ya+r/%C%nW75+/9+2+{/7.
/VUNVr+m 7E`b% E3\+ 31/8`ya+r/%C%nW75+/9-5+4+-5d
B+2..!,3GH0 I %-DEd
(+(:31/8`y )+':31/8`y +P:31/8`y *+*P31/8`y
( ) ( )
2
2
2
2
2 2
2
2 4 2
2 2 2
2 2
0
1 . 1 .
+ Khảo sát công thức tính công suất: .
1 1 1
2 2
1
2

1 1
+ Đặt ta có: 2 , khảo sát hàm số
Khi rôto quay với tốc độ
x x
E NBS R NBS R
P I R
L
Z
R L
R L
C C
C
L
x f x R x L f
C C
n





= = = =


+ +
+






= = + +


+
( )
( )
( )
( )
( )
( ) ( ) ( )
2 2
0
1 2 1 2 1 2 1 2
0 1 2
2 2 2 2
0 1 2 0
1
thì 2 , 1
2 2
+ Khi rôto quay với tốc độ hoặc thì 0 có 2 nghiệm phân biệt và . Ta có: , 2
1 1 1 1 1 1 1 1
+ Từ 1 và 2 hay
2 2 2
max
x
x
b
P f min x LC R C
a

b
n n P P f x x x x
a
x x x
n n

= =
= = + =

= + = + =


2 2
2
1 2
0
2 2 2 2
1 2 1 2
2
1
=

n n
n
n n n

















+

+




#$?'^-p`I E+0%+2>%Q+%J
:
+;$::L<39 -?%-575+o@`5=
->7+S=/ 1/-pV/75++2 R\+4+-5a-p` -?%-575++2 R\ 8*
Ng/=/ /_C/t =->779+r/%CQ+=6/ir/R9
F$8$::G$8'::$8Z::H$8$(:
u
i
B
0
I
0

3
2
U
6


=
tức thời
P
B
3
2

( ) ( )
( ) ( ) ( )
0
0
tức thời
tức thời
+ Tại thời điểm
3
6
2
+ Công suất tức thời: cos cos 200 cos 200 cos
2
3 1
200
0 cos 200 cos 0 cos 200
2 6 6 600
u i u i

u i u i
i I
U
u
P UI UI t UI t
T
P t t t s







=


=


=






= + + + = + + +




+ = + + + = + + = = = =





#$@'^7.-p`I E+0%-U+2/VUp%n/J$*:#39 -?%-575+@`
/x7-pVWn-p39+%.+g7%?o -?%+%.+g7+27_+7.i2 NNN7W1/-p
b% 75+R9JP +;$::Y 8Z<;F<7FiN-2/a1/-pb% 75+R9JP+;$::h 8$*<;F<
.4+g7o39-p%/+2/VU
F$8 39$8;' <7~G'8;$: <39$8;' <7~
'8 39$:YP8 ~H'8;$: <39$:YP8 ~
( ) ( ) ( ) ( )
( ) ( ) ( )
( ) ( ) ( )
( )
= = = + =
= = = + =
=
= =
2
2
1
1
2 2
2
2
2
2 2

120
+ Khi mở, mạch điện gồm , , 30 30 , 1
4
120
+ Khi đóng, mạch điện gồm , 30 2 3 2 , 2
2 2
+ Từ 1 và 2 2 Loại và .
+ Xét đáp án có: 30 khi
L C
C
C L C
L C
U
K R C L Z R Z Z
I
U
K R C Z R Z
I
R Z Z Z A C
B Z Z
( )
( ) ( )












= = =





+ = = =




1

2
mở cộng h ởng 120 2 cos 100
6 6
Khi đóng 30 30 dùng số phức 30 đúng chọn đáp án .
u i
C
K u t V
u
K Z i Z B
i
#$A'pA/-Sc+V%E0vT`%D+S6/-S=/DE7.` 3\-pA/
`V-S=/DER9$:G@p%%CV%E0g-pA/R\Tf:@%+r/%Cn/-p+m
i%D+S9EA/*:39/t/%E-p`WT`a-pA/ `V+-S=/DE-2R9
(+$P* )+$:f +e* *+$*'

( ) ( )
2 2
2 2
1 1
2
2
2 1
2 2
2 1
1 2 2
1 1 2 1
2
2 2 2 1 2
1
1
cos 1
0,123
1 1,2
0,108 0
1,2
1 0,877
1,2. . 1,2
TT TT
H P
PR
H
U H P
H
H H
H H

P P
H H H
H P P H
P
H H H P H



= =


=



= + =


=


= = = =


#$'!. /+T-pI E+0%7.` +2-p`p%n/-U7Q+6/&:#p+r/%C+m /+T
6/:f39+r/%C%n-p-U7Q++m 26/f:O> /+T+2>5 /aS=/WRS\-p
I E+0%+2-p`p%n/$$:#/S= 7_+@` /+T9E3\7.-pVW%?Vx7\7_+39
RS\-ppVW+2/VU. I3\/VU9 %-DEd
(+*(Š )+$&Š +**Š *+*ZŠ
#$'!.7E@@+231/+%.T+C`/C`$:R?+%.Q+C` -?%+%.T+C`7_+39

/%xJ**:-pVW+%.T+C`V$J:39+%.Q+C`V*J*75+vi‚`iBb%  `1/•%+
39Q+I5i -?%+%.Q+C`7_+3\-VWJ*:a-p` -?%+%.Q+C`R9d
F$f#G**#*:#H*P#
VgR=
( )
( )
( )
( )
$ $ *
*
$
*
*
$
*
$
*


**: : $:*
$: $$ *:
**:
$:*: *:
:
*
*:
U r k r
k
U k R R
N

k
N
U V
U V
U
r
r
R

= + +



=


⇔ = + + = ⇔ =

=


=

= Ω


= Ω

#$'-575+@`"Q4/x7-pVW%?n+2%/i/



39+%.+g7%?+2+g7
i/
o

^39 -?%-575+7.-p`I E+0%+2/VUp%n/a-p`p%n/+m ++
-575+R9
 o

 )   *
*
= =
N-2 +2pQ+
(+
( )
*
o o 
f ‰ ‰ ‰= −
)+
*
o 
 e‰ ‰=
( )
110 V
( )
90 V
r
L
R
α

β
♦  +2
( )
0
180 cos cos 0,8
10
cos 80 90. .0,8
9
P UI I I A
β α β α
α

+ = ⇒ = − = −


= ⇔ = ⇔ =


♦ "-UR+V/ 7/+FG +2
( ) ( )
2 2 2
2 2 2
2 . cos
110 90 2 .90. 0,8 23,833
R R R
AB AC BC AC BC
U U U V
β
= + −
⇔ = + − − ⇔ =

♦ v-2%EV 
( )
23,833
21,5 chän ®¸p ¸n C.
10
9
R
U
R
I
= = ≈ Ω →
+
( )
o 
( e ‰ ‰= −
*+
o 
‰ ‰
e
*
+
=
%!&!'#+m 75+Sa3l
( )
*
*
*
* *
o 
o


  *
  
(
*
+ 
*
* * P *
 
+ −
 ÷
+ −
 
α = = =
( )
o 
(
  +  $
P *
− = α =
 o
( ( '
   *
P * P * P *
⇒ = − = − =
( )
* *
*
* *
  

 ' e
    *
'*
* P *
   
⇒ = − = − =
 ÷  ÷
   
v;$<39;*<%EV 
( ) ( )

 o  o 
o 
 e
( e   ( e ‰ ‰ 
  (
= ⇔ = − ⇒ = −

⟹ =
#$8'!.75+  /o3\+%ik  /R9*ŽG -?%++n7.-p+•:J
C
&
$:
f

π

 %-2+75+  /4H75++2-pVWB  /-pvV/75+_?+,7;+%
ik  /+m 75+I"7Sir/-†<S/ +m +S=/ 1/b% +%./g7"=/ 
39+Q %:(  / -2/g7-7.ƒ 5=->7 J

*a +m +S=/ 1/b% +%.DER9
F*;7F< Gf;7F< :f;7F<
*+:(;7F<
%!&!'
J*π
LC
JMoJ
*
*
P
π
T

G +ST/ 1/-Ry+-?%
*
*
:
LI
J
C
Q
*
*
:
JM•
:
*
J
LC
Q

*
:
J
*
*
:
*
P
T
Q
π
JM•
:
J
T
Q
:
*
π
Jf$:
Y'
FJf7F
G +S=/ /g7"=/ +Q %:(/g7-7.ƒ  %J*JP:( /g7-*
P
R?
YJM5=->7J*a +m +S=/ 1/b% +%.R9J

9
P
:

*
I
9"C(+,D,*
#$ 75+  /RSW/o
$

$
39o
*

*
3\
$
J
*
J:$Ž~o
$
Jo
*
J$ŽG -?%+-p
+n
$
-@p%-p@Z#39n
*
-@p%-p@$*#Vx+75+  /=/ /_Ci>
vi 75+  /_-?%  /ap%-p@V*n
$
39
*
+Rp+ %'#d

F
Z
$:
Z−
G
'
$:
Z−

*
$:
Z−
H
$*
$:
Z−



o






α
%!&!+%ia  /+m ++75+  /J*π
LC
J*π

ZZ
$:$:$:
−−
J
$:
$:*
Z−
π
J*$:
YZ

G>%Q+-p`/t ++g+4++m  n-p
%
$
J$*+ω;#<)%
*
JZ+ω;#<
%
$
s%
*
J$*+ωYZ+ω;#<JZ+ω
%
$
s%
*
JZ+ωJ[';#<YYYYM+ωJ[:(JM+
T
π
*

J[:(9K
C!
9
Z
T
9
'
$:
Z−
L =)
#$"!. "` V R-^5->7]V7^-C`V 7.2/V%E0"`ST/R973\7^
`z// /7./2+P(
:
S\/R+ 2/9E`gI5V?/-pRVxVWR5/^`7^-CW->7!
iVCJZP::i7D/-pR+S7.R\`+?%W + $::i7V7^-C$
`yJ'$:
YP
V .9+%/]!
F*:$Zi7G':$Zi7$::i7H*::i7

%!&!> 9+%/]! /2+ϕJ∠]]}!‡‚ 7/+]]}F
]]}J)]}FJh)βJ∠]}]FJ&:
:
hP(
:
J$'(
:
"o97
:
$'(

• AO
J
*


α
OO
YYYYM
*

α
J
AO
OO


$'(
:
J:Z&Z
YYYYMαJff*(
:
YYYYYYMϕJ'Z:
:
s*e:
:
sff*(
:
ϕJ$e(
:
J$e(Z:'$:

YP
V J::'$(V 
$.B9Eϕ9F8"+>F+
8
MC9F>MC+,D,(
#$>'!5+  /WR39+m 7.7E% /x7+%.DE%?+g7+2 4+g7o
:
397.n-p+2-p
%/
:
i-27E%-Sc+2/-pv+2S\+2/
λ
:
@%{/n-p// %+{/-p%/
:
7_+@`
3\ %Vx7_+//3\n
:
+m 75+  /i-27E%-Sc+2/+2S\+2/
(+
:
; $< 8n n
λ
+
 )+
:
8 n
λ
 +
:

n
λ
 *+
:
8; $<n n
λ
+

%!&!λ
:
J*π+
::
CL
λJ*π+
CL
:
#\J
:
h
n
C
:
J
n
nC <$;
:
+
YYYYYM
λJ*π+
CL

:
J*π+
::
$
C
n
n
L
+
J*π+
::
CL

n
n $+
Jλ
:
n
n $+
 =,D,(
#$?'!.75+  /oR‘SW/- /4+p  /-pv43\+%ikN‘p%FG
R?RScR9 g+m n5=->7
$
gF+-pST/39n- /-Sc++-p@=->7
*
J
'8Pa-p++m gF39+0%1/-pb% +%.DER9
F+-pST/vF-@GG+-pST/vG-@F
+-pD7vG-@FH+-pD7vF-@G
ϕ

]}
F
α
]β
!
( )
2
A t
q
i
( )
2
B t
( )
1
A t
( )
1
B t
B

+ Tô ®ang tÝch ®iÖn cã 0 ®ang t¨ng nh h×nh vÏ.
+ Tô tÝch ®iÖn 0.
0
+ Trªn vßng trßn: chiÒu i tõ
0
A A
B
A
B

A Q Q
B Q
i
A B
i


> ⇒


<


>


⇒ →


<


#$@!.+{7 ///+@%/x7 9`?-T_++@%39C7mE9E
oJf77+@%C+m ++9`?-3\mER?RScR9
$
J
*
39
*
J

'
S\/2+\JZ:
:

>79%+m *+{7 R2//p %a V./+m +{7\+2/VUR\C6/
FP;
(
'
Y
'
$
<77G(;
(
'
Y
'
$
<77P;
e
'
Y
'
$
<77HP;
(
f
Y
'
$
<77

#$@%!&!gƒ+{7\+2++->7\•
$
39•
*
H/2+\JZ:
:
 V./+m +{7\
 J•
$

*
8*
2+iy+I5+m * /V/C7mE
V
$
J
$

n
i
J
*
Z:
:
J
P
Z
;V
$
≈'f

:
<YYYM V
$
J
(
'
V
*
J
*

n
i
J
'
Z:
:
J
*
$
;V
*
J':
:
<YYYYM V
*
J
'
$
>79%+m *+{7 R2//p %a->7R2+m  

9`?-T_++m   \WVa +m +{7\V{/ %
H-2•
$

*
J
$

*
J
*
s
$
J•
$
; V
$
Y V
*
<Jf;
(
'
Y
'
$
<77
YYYM JP;
(
'
Y

'
$
<77`F
#$A'V//p730/  /ig/++/t  i"/R9$77ig/++v7^
`z/+Q  i"-@79b% R9*(7’/+@%-@ i"/x7 /-T_+V/
3{//igi@+2S\+2/“$39“*J“$h:$Ž7Ng/++/?C/t  3D/+{/
79%3\3DV%/D7R9e(77‡+-U“$
F:PŽ7G:ZŽ7:(Ž7H:'Ž7
H +2iA/++*3D/R@`+{/79%3DV%/D7/R9ig/3DV{/

t/3D/V%/ %B 7g -@-DE"7+2>ƒ-Sc+-`
#$8V/D/30Fig/++/t *i"R9:f77ig/++v*i"-@79R9*7
/%x+@%-x/=*Q+I5-T_++2S\+2/e(:739(::7BV/3{//  +2 V./
$:77;IQ/ %b% #<+2 %3D/+279%//79%+m #d
FZGP'H(
%!&!#UV3D/+279%//79%3D/V%/D7IJi
$

$
Ji
*

*
i
$

$
Ji
*


*
YMi
$
λ
$
Ji
*
λ
*
YM'i
$
J*i
*
YMi
$
J*39i
*
J';3\J:±$)±*)±'<
IJ*
$
J'
*
YMIJ*
a
D
$
λ
J*
'
Z

$:f:
$:e(:*


J'e(;77<
3D/79%//79%3D/V%/D7Y(uIJ'e(u(YMY$''uu$''

$

*

$
•
*
YMY$≤≤$YM-N8.!,3G;JY$):)$< =,D,+
#$8'V//p7/  /+2QT+2/λv:Pµ7-@:eµ7Ng/++/t  /%xi@
c`R9 J*77v /%x-@79R9HJ$*75->7!++3D/V%/D77.ig/I
!
J$&(77+2
t/Q+I59+3D/
F+2$Q+I5G+2'Q+I5+2fQ+I5H+2PQ+I5
#$.!&!'5!+23D/@%I
!
J
Nn ∈
'
 *$&( '*(
 ; <
 $*$:
M

M
a XD
x n mm m
a n D n n
λ
λ λ µ

= ⇒ = = => =
!9 λJ:Pµ7YM:eµ7
'*( $ $
:P :e
:P '*( :e
'*( '*(
f$ PZ (Zef
:P :e
n
n
n n n
≤ ≤ ⇒ ≥ ≥
≥ ≥ ⇒ ≥ ≥ ⇒ =
JM+2PQ+I5/,`V%/W!Q/3\J(Zef
@39;$< +2S\+2/R9λ
(
J:Z(µ7)λ
Z
J:(P*µ7)λ
e
J:PZPµ7)λ
f
J:P:Zµ7

#$.!&!'B*O?'
'*(
; <f x
x
=
9P(E9O*9POQ9
RST$& UV&.VWD &!- =9"X>X?X@
#$8'V//p7•YD/30/  /@% i"/-T_++2S\+2/

$
J:ZŽ7aV79b%  CE+2Z3D/R@`++ %&77@%+@% i"-x/=
 Q+I5“
$
39“
*
a/S= CE5!++3DV%/D7$:f773D+279%//3DV%/D7V/
ig//t !393D/V%/D7+1+2*3UV3D///79%3DV%/D7GS\+2/+m Q+
I5“
*
R9
(+:PŽ7)+:'fŽ7+:Z(Ž7*+:eZŽ7
%!&!Ng/3D
$
J&778;ZY$<J$f77

$
$:f
Z
$f
M

x
i
= =
5!R93D/,+Z+m Q+I5“
$

Ng/++/t 3D/+{/79%39/?C3D/V%/D7R9
IJ
$:f
'Z
'
mm=
Q/3\3D/,+ +m Q+I5“
$
H-2*
$
Ji
*
JM
$
$ * *
* $*
* ; <
D D
k m
a a k k
λ
λ λ λ µ
= ⇒ = =
#\iR9/%EiJ

*
$*
λ
V/P/VU+m Q+I5“
*
-|++•+2
Q+I5“

J:P”7+iJ'R9/%E =(
#$88'!.RA/imE+2/2++@b% /FJe
:
+@%C+m RA/i-3\ 7R9

J$Z:P*@%
39RA/i7. /V_/S\/2+\B/2+Rp+/t  R279%-B39 7R9
D

J:::P(V @%C
+m RA/i-3\/79%-BR9
(+
-
J$Z::( )+
-
J$(fe* +
-
J$(e&f *+
-
J$(Ze*
%!&!
h2+Rp++m 7• R9HJ;s$<F

h∆HJH

sH
-
J;

s
-
<FJM
-
J

Y∆H8FJ$Z:P*s:::P(8:$**$

-
J$(Ze'
:9M
Y:9λ
$ ''(

8

"
>
?
@
A
+>"
+@88
+@"

+>"
+">
+>
+>
:'Z$$
∆H
#$8+V//p7%//+2S\+2/(::7R9+D-S=/+ 53%r//2+v$
\79!oy+-?%/S= CER9$+4+-5/  HU+!9!V I  i"$39*-@i5
UVp%A/RSc//R?Q$a U+R9$8e7>A/RSc/5R5Vp%a`gU+79
I 7CR9$Z8'(7Ng/++ i"$39*R9
F$f77 G*77 $77 H:(77
%!&!V//7•D/3UV3D/393D
I

Ji)I

J;iY:(<3\iJ$*'
>7++3DV%/D7I
gSRy+-?%5R93D/,+i
IJiJi
a
D
λ
;$<
NU+79V I R?QC
5R93DQi)IJ;iY:(<
a
DD <;
$
∆+

λ
;*<
NU+79V I 7aR?9E5lR93D,+;iY$<
N-2IJ;iY$(<
a
DDD <;
*$
∆+∆+
λ
;'<
!^i+IJ
*
a
;P<
v;$<39;*<;'<iHJ;iY:(<;Hh
e
$
<J;is$(<;Hh
e
$
h
'(
$Z
<JM*9CXM9
IJi
a
D
λ
J
*

a
JM
*
J*iλHJ*P:($:
YZ
$JP$:
YZ
JM79+
8
C9CC+ =)
#$8"'V//p7/  /+2QT+2/λv:Pµ7-@:eµ7Ng/++/t  /%xi@
c`R9 J*77v /%x-@79R9HJ$*75->7!++3D/V%/D77.ig/I
!
J$&(77+2
t/Q+I59+3D/
F+2$Q+I5G+2'Q+I5+2fQ+I5H+2PQ+I5
)H!'5!+23D/@%I
!
J
Nn ∈
'
 *$&( '*(
 ; <
 $*$:
M
M
a XD
x n mm m
a n D n n
λ

λ λ µ

= ⇒ = = => =
!9 λJ:Pµ7YM:eµ7
'*( $ $
:P :e
:P '*( :e
'*( '*(
f$ PZ (Zef
:P :e
n
n
n n n
≤ ≤ ⇒ ≥ ≥
≥ ≥ ⇒ ≥ ≥ ⇒ =
@+2PQ+I5/,`V%/W!Q/3\J(Zef
@39;$< +2S\+2/+m +y/R9λ
(
J:Z(µ7)λ
Z
J:(P*µ7)λ
e
J:PZPµ7)λ
f
J:P:Zµ7
#$8>'@%R?RSc Q+I5+2S\+2/
$
λ
JZ::739
*

λ
J:'
m
µ
397.C7i7R5a,-Sc+++
b% /"+23D++4+-5R?RScR93
$
J*$:
(
78393
*
JP$:
(
78@%6/Q+I5+2S\+2/
'
λ
J:*
µ
7a
3,++4+-5+m b% /-pƒR9
$8e7$Z8'(7
H
H

•••
F($:
(
78G*
e
$:

(
78
Z
$:
(
78HZ$:
(
78
%!&!F`n/FI 
*
*
*
*
$
$
*
$
)
*
$
mvA
hc
mvA
hc
+=+=
λλ
<$<;;
*
$
<

$$
;
*
$
*
*
$*
vvmhc −=−→
λλ
*
'
'
*
$
mvA
hc
+=
λ
<*<;;
*
$
<
$$
;
*
$
*
'
$'
vvmhc −=−→

λλ
oCE`;*<`;$<
smv
v
vv
vv
8$:e**
$:P$:$Z
$:P
$$
$$
(
'
$:$:
$:*
'
$*
$'
*
$
*
*
*
$
*
'
=→=






=


λλ
λλ
%!&!
 +2
$
λ
hc
JFhO
-$
;$<
*
λ
hc
JFhO
-*
;*<
'
λ
hc
JFhO
-'
;'<
H3
*
J*3

$
JMO
*
JPO
$
;$<JMP
$
λ
hc
JPFhO
-*
;$}<oCE;$}<s;*<)P
$
λ
hc
Y
*
λ
hc
J'FJMFJ
'
hc
;
$
P
λ
Y
*
$
λ

<;P<
O
-'
J
'
λ
hc
YFJ+;
'
$
λ
Y
$
'
P
λ
h
*
'
$
λ
<J+
'*$
'$'**$
'
P'
λλλ
λλλλλλ
+−
;$<

O
-$
J
$
λ
hc
YFJ+;
$
$
λ
Y
$
'
P
λ
h
*
'
$
λ
<J+
*$
*$
'
λλ
λλ

;*<
v;$<39;*<
$

'
đ
đ
W
W
J
'*$
'$'**$
<;
P'
λλλ
λλλλλλ

+−
JeJM
$
'
v
v
J
e
9K1
8
91

e
9
e
+
"

CZL+ =)
#$8?' o?RSc+@%39+ r+m 7.@9b% /-p Q+I5-T_++2S\+2/
m
µλ
Z:
$
=
 39
m
µλ
(:
*
=
ap%-p@|7->1/b% /-pVp%i+ % R?\5b% /-p+m i7R5
R97+ rR9
(+
<;eP(: m
µ
 )+
<;e*': m
µ
+
<;ZZe: m
µ
*+
<;Zf&: m
µ

*%!&!'
hN{/

$
:$
$ h
Ue
hchc
+=⇒
λλ
λ
;$<)
hN{/
$
:
*
:*
*
'
hh
Ue
hc
Ue
hchc
==+=⇒
λλλ
λ
;*<
hv;$<39;*<
<;ZZe:
'
*
$*

*$
:
m
µ
λλ
λλ
λ
=

=⇒

#$8@ 'CRB/•R%V"I"C`n/i+++2S\+2/“J:PfŽ739`V +2S\+2/“}J
:ZPŽ7G@p%%C+m 4`b% /9ER9&:Œ(hiệu suất của sự phát quang là tỉ số giữa năng lượng của ánh
sáng phát quang và năng lượng của ánh sáng kích thích trong một đơn vị thời gian)`rr+m /i++
+@%-@V/$R9*:$*$:
$:
5`rr+m +{7/`b% /`V V/$R9
(+*Zf*e$:
$*
)+*P$PP$:
$'
+$'(f$$:
$'
*+*&f:e$:
$$
*%!&!r/%C+m /i++J
λ
hc
`rr+m /i++`V V/$
r/%C+m /`b% /}J}


λ
hc
}`rr+m /`b% /`V V/$
p%%C+m 4`b% /J

••
λ
λ
N
N
P
P
=
JM}J
λ
λ

J*:$*$:
$:
:&
Pf:
ZP:
J*P$PP$:
$'
 =)
#$8A'@%R?RSc'Q+I5-T_++2S\+2/"•Rp
($*$
'*$
=

λλλ
39+ r+m 7.@ b% /
-pa,-Sc+++"R"+Vb% /-p+23,+ -?%+4+-5ST/Q/39+2•Rp
kvvv $*
'*$
=
3\
k
6/
F
'
G
'8$

*
H
*8$
( )
*
*
*
*
*
*
*
*
P ;$<
*
;$< ;*< '
'

* *
 ;*< ' *
* * $
;'< ;*< $
Z *
;'<
$( *
hc mv
A
hc mv
hc mv
HD A k
k
hc mv
k
hc mv
A k
λ
λ
λ
λ
λ

= +



− ⇒ =




= + ⇒ ⇒ = ⇒ =
 

 
− ⇒ = −
 

= +


#$r/+m i7R5FR9'fZ"#)+m i7R5GR9P'P"#@%7.Q+I5+2?•J$($:
$(
…
39b%g+?%i7R5R976/c`i7FG-^+rR,`ab%g+?%+-p-@-p@+4+-5R9#7 I>b%g+?%
+-p-@-p@+4+-5R9$*(#7 IaS\+2/+m Q+I5-pv+@%39b%g+?%+2 R\IC`I•6/
F:$eZŽ7 G:*f'Ž7 :$f'Ž7 H:$*fŽ7
%!&!'r/+m c`i7R9+r/WC+m i7R5F39GQ+R9FJ'fZ"#
 +2•JFh"#
7 I
•}JFh$*("#
7 I
JM;•}s•<J:*("#
7 I
J:*(;•sF<
JM•}J$*(•s:*(FJM•}J$*(•s:*(F8
F8J'fZ$Z$:
Y$&
8ZZ*($:
Y'PY

J:&'*$:
$(
JM•}J$*(•s:*(F8J$Z'&$:
$(
…JMλJ9-ZYJ9F@8+
>
C9F@8[C+,D,
%!&!'
’`n/-UR%,FY‡ 
( )
( )
( )
( )
( ) ( )
$&
$( $(
'P
 $
$*(  *
$
:*( : *('fZ$Z$:
$*( $*( $*($($: $ZP*$:
ZZ*($:
*
A A
B B MAX A A MAX MAX A
A B
SAU A MAX
A
SAU A A SAU

SAU
hf A eV
hf A eV V V hf A eV eV hf A
A A
hf A eV
A
hf A hf A f f Hz
h
c
f
λ


 = +



= + ⇒ = ⇒ = + ⇒ = −




<



= +




⇒ = + − ⇔ = − = − ≈



⇒ =
( )
f
$(
'$:
:$f'
$ZP*$:
SAU
m
µ
= ≈
#$'o …"F`V +{7Q+I5+2S\+2/P::73\+r/%C:ZOo …"G`V +{7Q+I5+2S\+
2/“3\+r/%C:*OV/+{/7.-T3U=/ `R …"F`V /C`*R?`R …"G
`V !.+C`b% /+2igA/`/79%-B39Rn+@%{/R …"Gi+++C`b% /V
a2`V /79%
(+7 )+-B +39/ *+Rn+
♦ ‡‚V/$/DE +2
( )
.
0,6
2. 0,6 .
. 0,2 0,4
A A B B
B
B B A
P N

hc
P N N m
P N
λ λ
ε λ µ
λ λ
= = ⇒ = ⇔ = ⇔ =
♦ "-UR%,‡s+aS\+2/`b% /`gR\TS\+2/i++
.
PQ B
λ λ
>
♦ @-DE++"7lRy/y/ir/@R97 +-`+-y/\V6/S\+2/-BR9R\C+
-`G
#$'+7Q+A/RSc/+m ++V5/v/+m /%Eƒ-Vr-Sc+I+-U6/>%Q+
*
$'Z
n
E
n
= −
;"#<;J$*'–<@%/%Eƒ-VrC`n7.`rr+2A/RSc/*(("#aS\+2/R\
C+m Q+I579/%Eƒ-Vr-2+2>`V R9
F&eP$:
Yf
7 G$**$:
YZ
7 Pfe$:
YZ
7 H$ff$:

YZ
7
%!&!' +2
*
$'Z
n
E
n
= −
0+—Y—7J*f(Z"#oCE*f(Z"#+ $'Z"# +2
*(( '
$'Z $Z
=

*\71H0V&.3W9K91HC9JM
 7
* *
$'Z $'Z
— — ; < *(("#
* P
− = − =

/˜ R9/%Eƒ-Vr- /W7Q+A/RSc/;JP<N2+%E>v7Q+A/RSc/;3\JP<30!;3\
J'<a`V `rr+2S\+2/9C
* *
7 I
+ $'Z $'Z
; < :ZZ$"#
' P
= − =

λ
JM
Z
7 I
$&
+
$fe&((f$: 7
:ZZ$$Z$:


λ = =
 =*
%!&!'
 7 P *
* *
$'Z $'Z
— — ; < *(("# — —
* P
− = − = = −
JM!Q+>%
P '
* *
$'Z $'Z
— — ; < :ZZ$"#
' P
− = − = =>
'P f
Z
P'
$&

P '
+ ZZ*($: '$:
$fe&((f$: 7
— — :ZZ$$Z$:



λ = = =

 =*
#$8'!Q+A/RSc/+m /%Eƒ-VrWV5/v/-Sc+I+-U">%Q+
*
$'Z
n
E
n
= −
"#;J$
*'<++/%Eƒ-VrC`n++`+c`->+%E>RV5/i++i-2Q+I5+2
S\+2/i+ %0%C79++/%Eƒ+2>`V R9$:GS\+2//_CV/++Q+I5-2R9
(+::&($”7 )+P:(&”7 +:$*$e”7 *+:$:*e”7
%!&!Q+I5+2S\+2/i+ %79/%Eƒ+2>`V R9$:Q/3\J(

7
λ
hc
J—
(
s—
$

J$'ZY
*(
Z$'
;"#<J
*(
Z$'*P
"#J$':(Z"#
λ
7
J
eV
hc
:(Z$'
J
$&
f'P
$:Z$:(Z$'
$:'$:Z*(Z


J:&($$:
Ye
7J::&($”7,D,(
#$5D
Be
$:
P
+2iRSc/$::$'(%NRSc/+m TVr;TV<7

J$::fe%iRSc/+m `Vrr

;`Vr<7

J$::e'%$%J&'$!"#8+
*
A/RSc/Ri@V/+m 5DR9
Be
$:
P
F:Z'*!"# GZ'*$(!"# Z'*(!"# HZ'*$('!"#
*%!&!'
YA/RSc/Ri@+m 5D
Be
$:
P
O
Ri
J™7+
*
J;P7

hZ7

s7
G"
<+
*

J::Ze&+
*


JZ'*P&!"#
Y%EV A/RSc/Ri@V/+m 5D
Be
$:
P

Z'$*(
Z'*(
$:
lk
W
A
= =
!"#8%+Rr+
#$"!./ 7+C`2/I5V/7./DE`V P*$:
$'
5
β
Y
NRSc//%Eƒ+m +C9E`2/I59E
R9(f&''u)$uJ$ZZ$:
Y*e
kg%ikV|+m +C`2/I59ER9
(+$&e$:
f
/DE) )+$Z&$:
f
/DE) +$fZ$:
f
/DE) *+$ef$:

f
/DE
*%!&!' +2
: :
:
;$ < ;$ < 
t t
A A
m m
N N N e N e N t
A A
λ λ
β
λ
− −
= ∆ = − = − ≈
3a;uu<

f
:
 :Z&Z'
$Zf$:

A
m N
T s
N A
β
⇒ = ≈
#$>: G -?%+2*/ ;***<R9+C`2/I5+%ikV|/%Eƒ +1R5 %JP

F''&$:
*:
/%EƒG(P*$:
*:
/%Eƒ
'P&$:
*:
/%EƒH(:f$:
*:
/%Eƒ
*%!&!'Ta có:
⇒===
*:
:
:
$:'&'
$Z
*
$

A
Nm
NN
A
T
t
chọn A
#$?: !.+C`2/I5+2+%iaV|R9*:`yG -?%7.7š%+C-2+2iRSc/R9*/ %$P:`y
RSc/+C-|`DV|+2/VU9 %-DE
F$&'e(/ G::Z*(/ $*(/ H7.-`i+

*%!&!'RSc/+C-|`DV|
<*$;


:

−=∆ mm
J$&'e(/

(+
#$@: ‡‚`gQ/
*'*
&:
Th ›
*:f
f*
Pb + x
P
*
He + y
:
$−
œ

. ChC`2/I5+2+%ikV|R9 %=
/ J*a•5α395βR9
F
*
'
G'

'
*
 H
$
'
*%!&!'oGi*'*JPIh*:fJMIJZ
oG-p+‰&:J*IYEhf*JMEJP
•5α395βR9IEJZPJ'* =U$]'^L_H;M 4.`! /0
#$A: +{7TV_`-x/3U0
((
*(
!
 %-Sc+-x/3U`2/I5
(Z
*(
!
x/3U`2/I5
(Z
!
+2+%VaV|J*(39`I5V  
β
Y
 %b%Va_`
((
!
6/TVi@y+/S= CE
V/7š%V•/t /%Eƒ
(Z
!
39RSc//%Eƒ

((
!
J$:
Y$:
 %$:/=@`-2a•/t
/%Eƒ+m  R55VR9
(+$*($:
Y$$
)+'$*($:
Y$*
+Z*($:
Y$*
*+*($:
Y$$
*%!&!'  %b%Va_`
((
!
6/TVi@y+a/%Eƒ+m 
(Z
*(
!
/g7+1/%Eƒ
((
*(
!
ir/-† %$:/=JP+%ia/%Eƒ+m 
(Z
*(
!
/g7*

P
J$ZR?H-2a•/t /%Eƒ+m
 R55VR9
((
(Z
Mn
Mn
N
N
J
$Z
$:
$:−
JZ*($:
Y$*

 =
#$": G -?%+27.7š%+C`2/I5/%E+C‡3\+%iaV|Q7.5D‡ %i`2/I5
597.5D@%p EV/7š%+C-2•Rp/%Eƒ+m +C39+C‡R9ia%†+m 7š%
+CR9
(+
( )
R $ i
 
R *

=
 )+
( )
R $ i

 
R *
+
=
 +
( )
R *
 
R $ i
=
+
 *+
( )
*R *
 
R $ i
=
+

%!&!'
( )
( )
$ *
*
$ * * $ * *
$ $
* $ R * R $
$
*
R $

R *
t
T
t
T
t t t t
T T T T
t
T
t
T
Y
K
X
K K
t
K K
K T
K
t T


− − − −



= =
− = × ⇒ = + ×
= ⇒ = + ⇒ × = +
+

+
⇒ = ×
G

×