C a u 35. M o t ong Romghen c6 U A K = 500 (kV). T i m dong nSng cua electron khj den doi Catot. Coi toe dp luc dau cua electron k h i biJc ra k h o i Catot l a khong dang ke. Cho me = 9,1.10-"kg; e = 1,6.10-'"C
A. 5 . 1 0 - ' ^ B. 6.10-'* J C. 8 . 1 0 " ' ^ D. Q.IO"'* J .
C a u 36. M o t ong Romghen c6 U A K = 500 (kV). T i m bade song ng^n n h a t ciia tia X. Coi dpng nSng luc dau ciia electron k h i biifc r a k h o i Catot l a k h o n g daug ke. Cho h = 6,625.lO'^'j.s; c = 3.10' mJs; e ^ 1,6.10-'''C
A. 0,5 (.im B. 0,6 m m C. 0,8 n m D. 2,48 p m
C a u 37. M o t o n g Rpnghen phat r a t i a X c6 t a n so Idn n h a t l a 7,5.10'^Hz. T i m dpng nang electron k h i den do'i Catot. Coi toe dp luc dau cua electron kin bu-c ra k h o i Catot la k h o n g dang ke. Cho h = 6,625.10"^* J.s.
A, 4,96875.10-'''J B. 2,56767.10'° J C. 3,5367.10" J D. 8,8943.10"J
C a u 38. Mot o'ng Ranghen phat ra bude song ngan nhat la 4 pm. T i m hieu dien the giOfa A n o t va Catot ciia ong Ranghen. Coi td'c dp liic dau cua electron khi bure ra k h o i Catot l a k h o n g dang ke. Cho h = 6,625.10'^''J.s; c = 3.10** m/s e = 1,6.10-''C
A. 111124,5V B. 124097,5 V C. 124212,5 V D. 310546,8 V C a u 39. Cirdng dp dong dien t r o n g ong Ranghen la 0,64 mA. Biet dpng nang
ban dau ciia electron k h i burc ra k h o i Catot l a k h o n g dang ke. T i m so' dien t i i dap vao doi Catot t r o n g 2 phut. Cho e = l.e.lỐ^C
A. 4.10'''electron B. 24.lO'"* electron C. 4,8.10'^ electron D. 9,6.lO'^ electron
C a u 40. Hieu dien the giufa A n o t va Cato't ciia m o t ong C u - l i t - g i a la 15 k\
T i n h toe dp C L T C d a i cua cac electron dap vao Anot. Coi toe dp liic dau cu- electron k h i biic ra k h o i Cato't l a k h o n g dang ke. Cho biet k h o i luang va dien tich cac electron l a m,, = 9,1.10"^'kg; e = 1,6.10"'-'C
A. 86545m/s B. 86368906,5m/s C. 1492,96 m/s D. 3475,8 m/s C a u 41. Toe dp ciia cac electron k h i dap vao Anot ciia m o t o'ng C u - l i t - g i a I:
50000 km/s. De tSng toe dp n a y t h e m 5000 km/s, phai t a n g hieu di$n th(
dat v^o ong t h e m bao nhieu? Cho biet k h o i lu'png va dien t i c h cac electron la m , = 9,1.10-^'kg; e = 1,6.10-"^C
A. 1234,56 V B. 3564,84 V C. 1492,96 V D. 2346,85 V C a u 42. M o t ong C u - l i t - g i a eo cong suat trung b i n h 350 W, hieu dien the giua
A n o t va Catot c6 gia t r i 10 kV. H a y t i n h cUdng dp dong dien t r u n g b i n h va so electron t r u n g b i n h qua o'ng t r o n g m o i giay. Cho biet k h o i luang va diei tich cac electron l a m„ = 9,1.10-^'kg; e = 1,6.10""^C
A. 0,035A; 2,1875.10'^electron/s B. 0,035A; 3,1875.10'^electron/s C. 0,025A; 2,1875.10'''electron/s D. 0,015A; 3,1875.10"electron/s
Van de 8: HIEN Tl/ONG TAN S A C ANH SANG
fpHl/OfNG P H A P
•]. G6c lech giOa tia t6i tia 16 cua 5nh s^ng dOn sSc khi qua Ong kinh g6c nh6 D = ( n - 1 ) . A
2. KhoJing c^ch tCr m^u dd ddn m^u tim cua quang ph6 trSn m^n A
Ax = AM(D„,,„-D.„)
hoSe ( H i n h 1)
Ax = AM(n,,„ - n j „ ) . A
( H i n h 2)
Man
tim Ax
Vdi: Dum = ( n t ™ - l ) - A ; D,,^ = ( n a , , - 1). A Trong do:
* A M : Khoang edch tCf canh ciia iSng k i n h den m ^ n (m)
* A x : Khoang each tCr mau do den niau t i m ciia quang phd t r e n m a n (m)
BAI TAP MAU
B a i 1. De quan sat sir t a n sac ciia a n h sang t h i ngu'di t a chieu mot chum t i a sang hep, song song vao canh ciia mot l a n g k i n h c6 goe chiet quang l a 5"
theo phuang vuong gdc v d i m a t phSng p h a n giac cua gdc chiet quang.
Chum t i a sang dupc chieu sao cho c6 m o t p h a n k h o n g qua ISng k i n h . D a t mot m a n (M) vuong gdc vdi phuang ciia chCim t i a t d i va each canh ciia iSng k i n h l a 80 cm.
a) Luc dau ngudi t a chieu chCim sang dan s^c mau vang. T i m k h o a n g each giaa ha i vet sang t r e n m a n . Biet r k n g chiet suat ciia ISng k i n h doi v d i anh sang vang l a 1,65.
b) Sau dd ngUdi t a chieu chum sang tr^ng. T i m khoang each t i i mau do den mau t i m ciia quang pho lien tue quan sat dirac t r e n man (M). Biet chiet suat cua iSng k i n h doi vdi mau dd va mau t i m la n,],-, - 1,61, nt,m - 1,68.
Tom tat . A = 5^'
• A M = 80 cm a) T i m Ax
Cho 1,65 b) T i m Ax.
Cho n,,„ = 1,61 ntim= 1,68
' HUcfng dan giai
a) Khoang each giOra hai vet sang t r e n m a n . A
A M
Do goc nho nen tanD ằ D ( * ) ^ D = Ax
A M Ax = D . A M
<^ Ax = (n - D A . A M <^ Ax = 0,0153(m) b) T i m khoang each tCi mau do den mau t i m cQa quang pho Hen tuc tren man.
• tan M A D = M D
• t a n M A T = A M M T A M
ô M A D
* M A T ma M A D = D,,<i = (n,,6 - D A
M A T = Dt,m = (nu„ - D A Ta c6: Ax = T M - D M
<^ Ax = A M . M A T - A M . M A D
^ Ax = AM.Dum - AM.Ddo
^ Ax = A M ( D „ „ - D , J (5) Cung CO the viet each khac The (3), (4) vao (5)
( 5 ) ^ Ax = AM(n^,„-nj,).A (6) The so vao ( 6 )
5::
tim
(6) -> Ax = 0,8(1,68 - 1,61).
180 Ax ô 4,884.10 '*m = 4,884 m m
B a i 2. M o t idng k i n h c6 goc chiet quang la 6° l a m b^ng loai thuy t i n h c6 chiet suat n j = 1,524 doi vdi hdc xa Xi - 0,656 nm va ng = 1,532 doi vdi bufc xa hi - 0,434 (.im. Mot t i a sang trSng r o i vao mot mat ben cua k i n h dudi goc t d i i nho. T i m goc giOTa hai t i a 16 iifng v6i hai biic xa Xi va X2. ^
Tom tat
•A = 6 " = 6n 180
• n , = 1,524 (rad)
HUdng dan gidi
N h a n xet: Day la bai toan lang k i n h c6 goc nho nen ta c6 the ap dung cong thiife:
D = (n - D A
I Xi = 0,656 |im , n2 = 1,532 UK2 = 0,434 Mm
^ T i m AD = ? I • Doi v6i biJc xa ^2
• Doi vdi biJc xa ki
D i = (m - D A = (1,524 - 1).
= 0,054845 (rad)
671
180
D2 = (nz - D A = (1,532 - 1) = 0,055682 (rad) 671
180 I V$y goc lech giiJa hai t i a
AD = D2 - D i
6 ijfng v6i hai biJc x^ Xi va ^2 AD = 8,37.10 "(rad)
B a i 3. M o t chum t i a sdng t r d n g song song v 6 i true chinh ciia mot thau k i n h thuy t i n h c6 hai mat loi giong nhau ban k i n h 20 cm c6 chiet suat do'i v 6 i bufc xa >ii la n i = 1,524, doi v6i bufc xa X2 la na - 1,532. T i m khoang each hai tieu diem cua thau k i n h iing v d i bufc xa A.i va X2.
Tom tat R = 20 cm n, = 1,524 n2 = 1,532 T i m Af = ?
• Do'i vdi bufc xa Xi
^ = (n, - 1)
Iliidng ddn gidi
N h a n xet: Mudn giai bai toan nay t h i can biet cong thiJe ciia thau k i n h va qui ir6c dau ciia cac mat eau, m a t ph^ng cua thau k i n h .
( 1 1 + •
^1 ^ 2 . (1)
V6i Ri = R2 20 em (do 2 mat cau giong nhau v^ deu Ik mSt l6i nen R i = R2;
R,, R2 > 0)
1 . Y i n
(1) -> f = (1,524 - 1 )
• Doi v6i biJc xa X2
fi = 19,08 c m
j - =(1,532 - 1)^
<^ f2 = 18,79 cm
I. Vay Af = f, - = 19,08 - 18,79 o Af = 0,29 cm
B a i 4. Chieu mot chum anh sang t r i n g song song, hep coi n h i i mot t i a sdng SI vao mpt be niidc c6 dp s&u 80 em v6i goc t 6 i 45°. DiTdi ddy be c6 mot guong phang dat song song v 6 i mat rnidc. T i m chieu rpng cQa day mau ma ta thu dupe 6 ehCim sang 16 ra k h o i mat niidc. Cho biet chiet suat cua n\idc doi v6i anh sdng t i m la nt = 1,34 va doi vdi anh sdng do la n^ = 1,33.
Tom tdt HU&ng ddn gidi
. h = 80 cm N h a n x6t: De giai b ^ i tap nay t h i chiing ta can , i = 450 n ^ m ro h i e n tuong khuc xa a n h sang, hie^
• nt = 1,34 tucfng phan xa a n h sang va cac cong thufc (nj sij^
• n<, = 1,33 i = n2 sinr, i = i'...) va each ve dudng d i t i a sang, T i m Ax = ?
Neu goi Ax la chieu rong cua day mau ma ta t h u duoc d chiim sang 16 khoi mat nUdrc t h i tijf h i n h ve ta c6:
c o s i = Ax J . J .
Ax = JtJd.cosi (1) T i m JtJ<t
Xet A vuong I H I t tanrt = I H
H I . tanrt = I H nen IJt = 2 I H = 2htanrt Xet A vuong IKId
I K I K tanr,! =
K L
I X L - 11 J M
- T T 1 - 1 /! 1 /I '
_ L _ t * L .
/ 1
V' / '
' \ 1
V
II Id
=> I K = h.tanrd nen U& = 2 I K = 2 h t a n r j
Ti^ h i n h ve ta c6: J J a = U d - U t ^ JtJ.i = 2htanrd - 2htanrt
<^ JtJ.i = 2h(tanrd - tanrt) (2)
M a t khac ra, rt se dugc t i n h tii cong thuTc khuc xa k h i t i a sang truyen tu khong k h i v^o niTdc.
• Tia do: n i s i n i = n2sinrd
-> l . s i n i = nd.sinr,] (do n i = 1, n2 =nd) <-> r,t = 32,11
• Tia t i m : n i s i n i = nasinr
-> l . s i n i = nt.sinrt<-> rt = 31,84°
The (3), (4) vac (2)
(2) ^ JiJd = 2.80 (tan32,ll° - tan31,84°) ^ JtJd'ô 1,04 (cm) The (5) vao (1)
(1) ^. Ax ô l,04.cos45'^
Vay Ax ô 0,735 cm
B A I T A P T R A C N G H I E M
C a u 43. De quan sat sif t&n sic cua d n h sang, ngUdi t a chieu mot chiim ^^'^^
sang song song, hep vao canh ciia mot ISng k i n h (c6 goc chiet quang A = ' theo phiiong vuong goc v d i mat p h i n g phan giac cua goc chiet quang, sao cb"
mQt phan cua chum sang k h o n g qua ISng k i n h . Dat mot m a n a n h E v u o i v
(3)
(4) (5)
P g6c vdi phifomg cua chum t i a t d i cdch canh ciia i S n g k i n h mot doan x.
Ngu'di ta chie'u mpt chum sang don sdc v^ do dUdc khoang each giiJa h a i vet sang t r e n man Ik 8,5 cm. Biet r k n g chiet suat cua l a n g k i n h doi vdi a n h sang nay l a 1,61. T i m x.
A. 0,547 m B. 1,543 m C. 1,996 m D. 2,565 m
C a u 44. De quan sat s u t a n sac cua a n h sang, ngudi ta chieu mot chum a n h sang t r i n g song song, hep vao canh ciia mot l a n g k i n h (c6 goc chiet quang A = 6") theo phi/ong vuong goc v d i mat p h a n g phan giac cua goc chiet quang, sao cho mpt phan cua chCim sang khong qua l a n g k i n h . Dat mpt m a n a n h E vuong goc v d i phu'dng cQa chum t i a t d i va each canh cua l a n g k i n h 2 m. H a y xac dinh chieu rong til mau do den mau t i m cua quang phd l i e n tuc quan sat difdc t r e n m a n E. Cho biet chiet suat ciia l a n g k i n h doi vdi mau do va doi vdi mau t i m I a n ludt bkng 1,61 va 1,68
A. 0,0146 m B. 0,367 m C. 0,285 m D. 0,254 m
C a u 45. Mot l a n g k i n h thuy t i n h cd goc chiet quang A dudc coi la nho, c6 chiet suat doi vdi a n h sang do va a n h sang t i m I a n li/dt la nd = 1,643 va nt = 1,685. Cho mot chum t i a sang t r ^ n g , hep r o i gin vuong goc vao mot mat ben cua l a n g k i n h . Goc giiJa t i a do va t i a t i m sau k h i ra k h o i l a n g k i n h
0,21". Goc chiet quang A l a
A. 3" B. 4° C. 5° D. 6°
Van de 9: LUClNG LANG KINH PRESNEL
PHl/OfNG PHAP
- Lifdng l a n g k i n h Fresnel la 2 l a n g k i n h cd goc chiet quang A nho, ddy diTdc dan chat nhau
- Ngudn sang S qua ludng lang k i n h tao t h a n h h a i a n h S1S2 la h a i nguon ket hop.
- Khoang each giuTa hai nguon k e t hdp S1S2 1^:
Trong do:
* a: Khoang each giufa hai nguon ket hop S1S2 (m)
* n: Chiet suat ISng k i n h .
* A : Goc chiet quang eiia ISng k i n h ( rad).
* d: Khoang cdeh tiT nguon S den hai ISng k i n h (m)
* D = d + d': Khoang each tii \\Xdng nguon ket hop den mkn (m)
* d': Khoang edeh tijr hai iSng k i n h den m a n (m) L: Be rong giao thoa trUdng (m)
B A I T A P M A U
B a i 1. H a i l a n g k i n h A i , A 2 eo cijng goc chiet quang A = 30', c6 day B chung, dirac l a m bkng thiiy t i n h , chiet suat n = 1,5. Mot nguon sang diem S dat trong mat p h i n g ciia day B each hai l a n g k i n h mot khoang d = 40 em phat anh sang don s^c, budc song la 600 nm. Mot m a n E each hai lang k i n h mot khoang d' = 60 cm.
a) T i n h khoang each giufa hai van sang l i e n tiep t r e n m^n.
b) T i m so van sang nhieu nhat c6 the quan sat dugrc t r e n man.
Biet 1' = 3.10-" rad.
Tom tat
• A = 30'
• n = 1,5
• d = 40 cm
• = 600 n m
• d' = 60 cm a) T i n h i b) T i m N ,
1' - 3.10-''rad.
HUdng dan gidi
N h a n xet: Nguon sang S phat ra chum sang ddn s&v t d i hai l a n g k i n h , moi lang k i n h cho mot ehijm sang bi lech ve phia day chung. Cac chum sang nay tUa nhu di/oc phat ra tir 2 nguon S i , S 2 la 2 a n h ao cua S du'cfc bdi hai lang k i n h . Liic nay ta eo the xem bai toan luSng lang k i n h t r d t h a n h mot bai toan thong thudng gio'ng nhurng bai toan tCr van de 1 den van de 6 ciia ehuong nay.
Trong do a la khoang each S1S2, D =.d + d' la khoang each tiT hai khe S i S : den man, 1. la birdc song anh sang dung trong t h i nghi^m.
a) Khoang van i (khoang each giiJa 2 van sang l i e n tiep t r e n man)
1 = (1)
• D = d + d' = 40 + 60 = 100 cm = 1 m
• ?L = 600 n m = 600.10"^ m
• a = ?
Ta CO a = S1S2 = 2(n - l)d.a = 2(1,5 - 1X0,4.30.3.10^ = 3,6.10"^ m = 3,6 m m The D, X, a vao (1)
600.10-^l ( l ) ^ i =
3,6.10' i = - . 1 0 "(m) 3
b) So van sang nhieu n h a t c6 the quan sAt duoc t r e n m a n Ta c6: Be rong giao thoa t r e n m a n
.3,6.10"^ ^ L = 5 . 4 . 1 0 - ' m = 5,4 m m L _ d'
a " d L d'
~ d ~ 0,6 0,4 L 5,4.10 :i ' 2i 2.-.10 -•1
k = 16 le = 0,2
So van sang N , = 2k + 1 = 2.16 + 1 ^ = 33 v a n sang
B a i 2. H a i l a n g k i n h c6 eung goc chiet quang A = 40' l a m bkng thuy t i n h . Chiet suat n = 1,5 c6 day gan chung vdi nhau tao t h a n h mot ladng lang k i n h . Mot khe sang S phat anh sang c6 birdc song I. = 0,6 urn dat t r e n mat ph&ng cua day chung eiia hai lang k i n h , each hai lang k i n h mot khoang 60 cm.
a) T i n h khoang each giOra hai anh S i , S 2 cua S tao bori h ^ i l a n g k i n h (coi S i , S 2 eijng n k m trong mot mat p h i n g vdri S ) .
b) T i n h khoang van va so' van sang nhieu nhat c6 the quan sat du'cfc t r e n man. Biet khoang each tii m a n t d i lifong lang k i n h la d' = 1,4 m.
e) H o i khoang van va so van sang quan sat dxioc se thay doi n h u the nao neu dich nguon S ra xa dan \\idng lang k i n h theo phiTcfng vuong goc vdi man E? Cho 1' = 3.10 ^ rad.
Tom tat
• A = 40'
• n = 1.5
• A. = 0,6 i-im a) a = ? b) i = ?
• N.s = ?
• d = 60 cm
• d' = 1,4 m c) i = ?
N , = ?
K h i dich ehuyen nguon S ra xa dan lu'dng l a n g k i n h theo phucfng vuong goc vdi m a n E.
1,4
HUcfng dan gidi a) Khoang each giufa hai khe 8182
a = 2(n - Dd.A
^ a = 2(1,5 - 1).0,6.40.3.10-"
a = 7,2.10 ^m = 7,2 m m b) • Khoang van i
. _ XD _ >i(d + d') a a
. 0,6.10-''(0,6 + l,4) . 1 0 , . , , ,
<-> 1 = — - — < ^ 1 = —.10 (m) 7,2.10"' 6
• So van sang quan sat dugfc t r e n m a n . Be rong giao thoa
L d' , d'
— = > L = — .a
a d d
^ L =
2i
. 7 , 2 . 1 0 " ' ' ^ L = 0,0168 (m) 0,6
^ ^ = 5 0 , 4 ^ 1 ^ = ^^
2.10.10- l i e =0,4
N e n : N , = 2k + 1 = 2.50 + 1 ^- = 101 van sdng
c) • K h i d i c h c h u y e n n g u o n S r a x a IxXdng I S n g k i n h t h i d t S n g . T a c6:
1 = XD X(d + d')
- > 1 = M d + d ' ) X Xd'
a a 2 ( n - l ) A d 2 ( n - l ) A 2 ( n - l ) A d N h U v a y k h i t a n g d t h i i g i a m n e n so v a n s d n g q u a n s a t dirge t S n g l e n v be r p n g g i a o t h o a trUcfng k h o n g d o i .
K h i S d i c h c h u y e n r a x a liTSng l a n g k i n h , d ^ co t h i i = X
0,6.10-'
2 ( n - D A 1 =
L 2 i
2(1,5-1)40.3.10 "
0,0168
= 5.10"^ m
= 168 k = 168 2.5.10'^
So v a n s a n g N g = 2k + 1 = 2.168 + 1 = 337 v a n s a n g
N h a n xet: T r o n g thiTc te t h i k h i n g u o n sang S d each x a l u 5 n g i S n g k i n h mot k h o a n g nao do t h i k h o a n g v a n se g i a m . K h i n g u o n S r a cang Idfn t h i i qua n h o n e n k h o n g con q u a n sat r o h i e n tiTdng giao t h o a v a liic n a y dp s a n g cua v a n giao t h o a se g i a m m a n h . K e t qua cf t r e n c h i m a n g y n g h i a ve t o a n hoc.
B a i 3. T r o n g t h i n g h i e m ve lu9iig ISng k i n h F r e s n e l ngU&i t a do dirge a = 3 m m , k h o a n g each tijf lifQng i S n g k i n h d e n m a n l a 1,7 m . Goc c h i e t q u a n g ciia m o i I S n g k i n h l a 0,01 r a d , c h i e t suat ciaa ludng l a n g k i n h l a 1,5. N g i r d i ta d i i n g d n h s a n g eo bude s o n g X = 0,6 |am. N g u o n S nhm t r o n g mat p h a n g chiifa d a y c h u n g cua lirSng lang k i n h .
a) Xac d i n h k h o a n g each tCr n g u o n d e n luang lang k i n h va dg r g n g cua triTcfng giao t h o a t r e n m a n .
b) T i m so v a n s a n g , v a n t o i xua't h i e n t r o n g t r u d n g giao t h o a .
c) T h a y n g u o n don s i c hhng n g u o n c6 d n h s a n g t r i n g c6 biTdc s o n g tif 0,38
|im < X < 0,76 |im. H a y t i m n h i J n g biJc x a eho v a n t o i tai d i e m M each v a n s a n g t r u n g t a m m o t k h o a n g 2,5 m m .
Tom tat
• a = 3 m m
• d' = 1,7 m
• A = 0,01 r a d . n = 1,5
• X = 0,6 \.im a) T i m d = ?
L = ?
b) T i m N s = ? N t - ? c) 0,38 f i m < A. < 0,76 ^ m
X M = 2,5 m m
T i m eac bufe x a eho v a n t o i t a i M .
HUdng dan gidi
a) • K h o a n g each tir nguon S den lii£fng l a n g k i n h a = 2 ( n - D d . A
a 3 . 1 0 ' - > d =
2 ( n - l ) A 2 ( 1 , 5 - 1 ) 0 , 0 1 d = 0,3 m = 30 e m
• D o r g n g cua t r i f d n g giao t h o a t r e n m a n . L d ' , d"
— = > I J - — .a.
a d d
^ L = ^ . 3 . 1 0 - ' <^ L = 0,017 ( m ) 0,3
b) T i m N , = ? Nt = ?
., , . M d + d') . 0 , 6 . 1 0 ^ ( 0 , 3 + 1,7) . ,
• K h o a n g v a n : i = = — <-ằ i = ^ — <r-> i = 4.10^ ( m ) 3.10
2 i
0 017 Jk = 2 1
JZl^ = 21,25 ^ J , ^
• So v a n s a n g Ns = 2 k + 1 = 43 v a n s a n g
• So v a n t o i Nt = 2 k = 42 v a n to'i c) T a cd:
X ; ^ = X M (1)
Do bufe x a cho v a n t o i t a i d i e m M n e n ^ X;^ = 2 (1) 2 i = 2 , 5 . 1 0 " ' ( k + 0 , 5 ) — = 2 , 5 . 1 0 XD
<^X=: 2,5,10 l a ( k + 0,5).D
2 , 5 , 1 0 ' . 3 . 1 0 ' , 3,75.10^
<^ X-
( k + 0,5).2 ( k + 0,5)
3,75.10 '
m a 0,38 <X< 0,76 |im - > 0 , 3 8 . 1 0 - ^ n < ( k + 0,5) ^ 0,76.10'^ m
<^ 4.43 < k < 9,36 - > k = 5, 6, 7. 8 V a y C O 4 biire x a cho v a n to'i t a i M .
B A I T A P T R A C N G H I E M
u 4 6 . De xac d i n h do I d n ciia m o t goc r a t til a ( g a n b a n g 180°) cua m o t l a n g k i n h , ngUcfi t a bo t r i so do giao thoa. BiJc xa dcfn sac c6 bude S # song X = 0,633 |.im dugc r g i l e n k h e
hep S tao r a c h i i m s a n g p h a n k i sau k h e , c h u m n a y r g i l e n d a y l a n g k i n h . T r o n g k l i o a n g M N t r e n m a n each l a n g k i n h m o t k h o a n g d ' = 1,20 m
q u a n s a t duge 4 v a n t o i l i e n t i e p l a 1,425 m m . T i n h goc a ciia l a n g k i n h , b i e t k h e S edeh l a n g k i n h m o t k h o a n g d ' = 30 em. C h i e t s u a t cua t h u y t i n h iJng v d i l a n = 1,5.
A . 176, 23" B . 177, 46° C. 178, 69° D . 179, 23°
C a u 47. So do giao t h o a g i o n g cau 46. BuTc x a dcfn s i c c6 budc s o n g A = 0 , 5 1 5 / / m dirge r g i l e n k h e h e p S t a o r a c h i j m s a n g p h a n k i sau k h e , c h u m n a y r g i l e n d a y l a n g k i n h . D o a n M N = 2,8 m m t r e n m a n each l a n g k i n h m o t k h o a n g d ' = 1,20 m q u a n s a t dirge 8 v a n t o i , d o n g thcfi c h i n h t a i M v a N l a h a i v a n s a n g . X a c d i n h c h i e t suat n cua t h u y t i n h l a m l a n g k i n h d o i v d i biJc xa n a y . B i e t k h e S each l a n g k i n h m o t d o a n 30 c m v a a = 179,23°.
E
A. n = 1,5 B. n = 1,55 C. n = 1,6 D. n = 1,65
C a u 48. H a i iSng k i n h c6 ciing goc chiet quang A = 15', l a m b&ng thuy tinh chiet suat n = 1,5 c6 day g^n chung v6i nhau tao t h a n h m o t lifSng ISng k i n h Mot khe sang S phat sang c6 hitdc song A =0,5 / / m dat t r e n m a t ciia day chung, cAch hai lang k i n h m o t khoang d = 40 cm. T i n h khoang each giCTa hai anh S i , S2 ciia S tao bdi h a i lang k i n h (coi S i , S2 ciing nkm trong m o t mat ph^ng v(Ji S). T i n h khoang v a n va so v a n sang quan sat dupc t r e n man, biet khoang each tiT m a n t d i li^Sng lang k i n h la d' = 2 m. Cho 1' ^S.IO"* rad.
A. m; 13 v a n sang B. — ^ i n ; 12 v a n sang
1500 1500 C. — ^ m; 13 v a n sdng D. — ^ m; 13 v a n sang
1400 1200 C a u 49. H a i lang k i n h c6 eung goc chiet quang A = 25', l a m bang thuy tinh
chiet suat n = 1,5 c6 day gan chung vdi nhau tao t h a n h m o t li^Sng lang k i n h Mot khe sang S phat sang eo hade song A = 0 , 6 jum dat t r e n m a t eua day chung, each hai lang k i n h m o t khoang d = 60 cm. T i n h khoang edeh giiJa haj anh S,, S2 eua S tao bdi h a i lang k i n h (coi S], S2 ciing nkm trong m o t mat p h i n g vdi S). T i n h khoang v a n va so' van sang quan sat duac t r e n man, biet khoang each tiT m a n t d i ludng lang k i n h la d' = 1 m. Cho 1' ^3.10"^ rad.
2 2 A. m; 34 v a n sang B. m; 35 v a n sang
9375 9375 C. — — m; 35 v a n sang D. ^ m; 36 v a n sdng
9375 9375 C a u 50. Trong t h i nghiem v 6 i ludng lang k i n h Fresnel, khoang each tii nguon
sang dcfn sac eo A = 0,5juni den liTomg lang k i n h la 20 em, khoang each tii ludng lang k i n h den man quan sat la 180 em, goc chiet quang eua ludng lang k i n h A = 0,02 rad va chiet suat ciia ludng lang k i n h n = 1,5. T i n h khoang eacli giufa 2 nguon sang ket hop va chieu rong ciia triiofng giao thoa quan sat tren man.
A. 4 m m ; 30 m m B. 4 m m ; 36 m m C. 5 m m ; 36 m m D. 6 m m ; 35 m m
C a u 51. Trong t h i nghiem v d i ladng lang k i n h Fresnel, khoang each tCr nguon sang don s^c c6 A = 0,6/jm den ludng iSng k i n h la 20 cm, khoang each tu lirSng lang k i n h den m a n quan sdt la 180 cm, goc chiet quang ciia ludng lang k i n h A = 0,01 r a d va chiet suat ciia liidng ISng k i n h n = 1,5. T i n h khoang van va so' van to'i xuat h i e n t r e n man.
A. 0,6 m m ; 30 van t o i B. 0,6 m m ; 31 van t o i C. 0,5 m m ; 30 van t o i D. 0,7 m m ; 3 1 van toi
C a u 52. Trong t h i nghiem v d i liiSng lang k i n h Fresnel, khoang each tiJf nguon anh sang t r ^ n g c6 0,38 |Lim < < 0,76nm den ludng lang k i n h l a 20 cm khoang each t i i lifdng lang k i n h den m a n quan sat l a 180 em, goc chiet
quang ciia lUSng i S n g k i n h A = 0,02 r a d va chiet sua't ciia lu8ng l a n g k i n h n = 1,5. T i m ta't c a cac t h a n h p h a n don s a c trong a n h s a n g t r ^ n g cho v a n t o i tai d i e m M each v a n t r u n g tarn mot k h o a n g 3,3 m m .
A. 5 B. 6 C. 7 D. 8
C a u 53. Mot luSng l a n g k i n h Fresnel cd gde chiec quang A r a t n h o chiet suat n = 1,5. Cach ludng l a n g k i n h mot doan d = 40 c m c6 d a t 1 k h e s a n g song song vdi c a n h eua l a n g k i n h . Cac ao a n h thu duac each n h a u 2 m m . T i n h gde chiet quang A eua l a n g k i n h .
A. 2.10'^rad B. 3.10"^ r a d C. 4.10"^ r a d 0 . 5 . 1 0 " ' ' r a d C a u 54. Mot ludng l a n g k i n h Fresnel ed gde chie'c quang A r a t nho chiet sua't
n = 1,5. Cach ludng l a n g k i n h mot doan d = 40 c m cd d a t 1 k h e s d n g song song v d i c a n h ciia l a n g k i n h . Cac ao a n h t h u dUOe each n h a u 1 m m . A n h sang chieu vao ludng lang k i n h cd biTdc sdng X = 0,6 f.im. Xac dinh khoang v a n va v i tri ciia v a n tdi thuT 6, biet m a n quan sat edeh liTdng lang k i n h d' = 2 m . A. 1,44 m m ; ± 7,92 m m B. 2,88 m m ; ± 7,92 m m
C. 1,44 m m ; ± 6,25 m m D. 1,44 m m ; ± 9,36 m m
Van de 10: B A N T H A U KINH B I L L E T PHl/ONG PHAP
- B a n thau k i n h Billet la m o t thau k i n h h o i t u duoc eUa l a m ddi theo m o t dudng k i n h qua quang tarn. H a i mVa thau k i n h duge tach r a sao cho d d i xiJng qua true chinh cu va cac vet cat song song vdi nhau.
- Nguon sang S qua hai niia tha'u k i n h tao n e n h a i a n h S1S2. H a i a n h n a y each nhau m o t doan la
V u n g giao thoa
a = S,S2 = ^ ^ . 0 ^ 0 2 d + d' + D 0,0,
L a
d + d' + D d + d'
1_1 J_
f " d ^ d'
Trong do:
* a: Khoang each hai a n h S1S2 (m).
* 0,02: Khoang each hai nuTa thau k i n h (m).
* d: Klioang each tir nguon S den hai nijra thau k i n h (m).
* d': Khoang each tCr hai anh S1S2 den hai nijfa thau k i n h (m).
* D: Khoang each lis S1S2 den m a n (m).
* L: Be rong giao thoa trUdng (m).
BAI TAP MAU
B a i 1. M o t thau k i n h hoi tu eo tieu cif f = 30 cm dudng k i n h vanh 4 em dirge ci/a doi theo mot difdng k i n h . Sau do hai niira thau k i n h du'oc tach ra xa nhau mot. khoang 4 m m (nhd chen vao giOa mot scfi day hoae mot thoi k i m loai). M o t khe sang hep song song vdi du'dng ehia hai nufa thau k i n h , dat each dirorng ay mot khoang d = 60 cm. Khe sang S phdt anh sang dan sdc CO birdc song k = 0,5 (.im. Dung m a n E dat edeh hai nufa thau k i n h mot doan Ax de quan sat du'Oc cac van giao thoa.
a) T i m gia t r i nho n h a t cua Ax de c6 the quan sat diigrc cac van giao thoa t r e n m a n E.
b) Cho Ax = 2m. Tinh khoang van va so van sang nhieu nhat c6 the quan sat du'oc.
Tom tat
• f = 30 cm
• Dudng k i n h v a n h la
X = 4 cm
• O1O2 = 4 m m
• d = 60 cm
• A = 0,5 (.im
a) T i m A X m . n
b) Cho Ax = 2m.
T i n h i = ? N , = ?
a) Khoang each i\i S1S2 den ban thau k i n h Billet
1 1 1 , , d.f 60.30
f
Hitdng dan gidi Man
— + > d = d d'
<-> d' = 60 cm = 0,6 (m) d - f 6 0 - 3 0
TCr h i n h ve ta thay de quan sat duge van giao thoa t h i m^n E p h a i dat x;
ban thau k i n h hon diem I -> Ax > 01 T i m 01: Xet AIS1S2 ^ AIAB
s.s, ^ I S ;
A B 10
T i m S1S2, A B , I S '
(1)
8,82 = a = ? a = ^ .0,02 = ^ 4 r ^ = 0-004 = 8,10-ôm = 8 m m d 0,6
• A B = x + 0,02 = 0,04 + 0,004 = 0,044 (m) I S ' = 10 - S ' O = 10 - d' = 10 - 0,6
The vao (1) ( 1 ) - ^ 8.10 '
0,044 10-0,6 ^ S.IO-MO = 0,044(10 - 0,6) <^ 10 = — ( m ) 1 1 ,
l U 15 Vay gia t r i nho n h a t eua Ax phai la — (m) 11
15 b) • Khoang van i
Vdi D = Ax - d' = 2 - 0,6 = 1,4 m
Vay ( 2 ) - > i . M i ^ ^ i . 8,75.10- m 8.10^'
• Be rpng vung giao thoa.
Xet AS0,02 ^ ASBC: BC so;
0,0, ~ so
_ L d + d ' + D ^ d + d ' + D ^ ^
——- = >L = ; O1O2
0,0,
^ L = ^ ' ^ ^ O ' ^ - l ' i . 4 . 1 0 - . 0,01733 (m) 0,6
L 0,01733 k = 99
le = 0,02
So van sang nhieu n h a t eo th§' quan sat dirge t r e n man Ns = 2k + 1 = 199 van sang
B a i 2. M o t thau k i n h hoi tu mong c6 tieu cir f = 20 cm dirge e^t ra l a m hai phan bang nhau theo mat phang qua true chinh va vuong goc vdi tiet dien thau k i n h . M o t nguon sang diem S true chinh va each thau k i n h 80 cm.
a) Phai tdeh h a i nufa thau k i n h nay den khoang each nao (mot each doi xu-ng qua true chinh) de n h a n dirge hai anh S,, 82 cdeh nhau 1 m m . b) Dat mot m a n quan sat E vuong goc vdfi true chinh va each cac anh 8182
mot khoang D = 2 m. T i m do rpng eiia vung giao thoa t r e n m a n va birde song cua dnh sang trong t h i nghiem.
^ Biet khoang each giOa 1 van sang va mot van t o i lien tiep la 0,5 m m . Tom tat
• f = 20 cm
• d = 80 cm a) O1O2 - ?
Cho a = 1 m m b) D = 2 m
Hudng dan gidi Sii dung h i n h ve bai 1
a) Khoang each giufa hai nufa thau k i n h O1O2
• Khoang each tCr S1S2 den ban thau k i n h d.f 80
i - i 1
f ~ d d' d' =
d - f -em
T i m L = ? X = ?
• — = 0,5 m m . 2
• Khoang cdch 2 nila thau k i n h
T a c6:a= ^^0^0^
0,02 = a.d 1.10-^0,8 d + d' 0,8 0,8
o O i O j =7,5.10 "(cm) b) T i m L = ? ^ = ?
T i m L.
Xet ASSiSa c o A S B C
B C SO L _ d + d ' + D SjS^ ~ SS' ^ a " d + d'
(0,8 + - ' " + 2).1.10 '
^ L = ^ ^
, (d + d'+ D) d + d
L = 2,875.10 ' ( m )
0,8+ M
3
T i m X: • Ta c6 - = 0,5 m m -> i = 1 m m 2
.X='^= O 0 : ^ L 1 0 : ! ^ 0 5_io-e
D 2 X = 0,5.10*' = 0 , 5 n m
BAI TAP TRAC NGHIEM
C a u 55. M o t thau k i n h h o i tu mong c6 tieu cU la 60 cm duoc c^t r a l a m hai phan bang nhau theo m a t ph^ng qua true c h i n h va vuong goc v d i t i e t dien thau k i n h . M o t nguon sang diem S phat a n h sang don s^c dat t r e n true chinh va each thau k i n h mot khoang d = 1,2 m. Phai tach hai nijfa thau kinh nay ra den khoang each nao (mot each doi xufng qua true chinh) de nhan duoc hai anh Si, S2 each nhau 2 m m
A. 1 m m B. 2 m m C. 3 m m D. 4 m m
C a u 56. M o t thau k i n h hoi t u mong c6 tieu cU la 40 cm duoc c^t r a l a m hai phan bkng nhau theo m a t phang qua true chinh va vuong goc v d i t i e t dieii thau k i n h . M o t nguon sang diem S phat a n h sang dan s^c dat t r e n true ehinh va each thau k i n h mot khoang d = 1,2 m. Dat mot m a n quan sat E vuong goc v d i true ehinh va each eac a n h S i , S2 mot khoang 3 m. NgUdi ta do duoc khoang each til v a n sang t r u n g t a m den v a n sang bac 6 la 2,4 m m va ^ anh S1S2 each nhau 3 m m va do rong eua viing giao thoa t r e n m a n E. Tin^
bade song ciia d n h sang
A. 0,4/im ; 7 m m B. 0,4 jum ; 8 m m C. 0,5 ; 7 m m D. 0,5 / / w ; 8 m m
Cau 57. M o t thau k i n h h o i t u O cd f = 30 cm, dudng k i n h L = 6 cm, dugc cuTa
doi theo mot dudng k i n h . Sau do h a i nuTa thau k i n h duoc keo xa ra mot khoang e = 1 m m . M o t khe sang hep F song song vdi dudng chia h a i nijTa
thau k i n h , dat each dudng ay mot khoang d = 80 cm. Khe F phat a n h sang don sac A = 0,6jui)i . V a n giao thoa quan sat t r e n m a n E dat each hai nijfa
thau k i n h mot khoang Ax. Muo'n quan sat duoc van giao thoa t h i Ac t d i thieu phai bang bao nhieu?
A. 0,69 m B . 0,79 m C. 0,49 m D. 0,69 m
Van de 11: G l / O N G F R E S N E L
PHl/ofNG P H A P
- Guang Fresnel la h a i guong ph^ng dat nghieng nhau mot goc a nho.
- Nguon sang S dat trade guang se cho h a i anh S1S2 la h a i nguon k e t hop.
- H a i nguon ket hgp each nhau mot doan la:
a = 8,82 = 2d.a
Vung 0 L giao
thoa
Vdi: d la khoang each tCf nguon S den giao tuyen eua h a i gifcfng (m)
BAI TAP MAU
i B a i 1. Cho h | h a i gi/ong p h i n g G i , G2 dat sdt nhau va nghieng vdi nhau mot goc a r a t nho. M o t nguon sang S chieu a n h sang v^o m a t h a i giTong. Goi Si, 82 la anh eua 8 tao bdi h a i guang. M a n a n h dat each dudng t h i n g qua 81, S2 mot khoang 2 m. Budc song a n h sang ciia nguon la 0,5 (.im. NgUdi ta do daoc khoang each gitira ba van sang l i e n tiep la 2 m m .
a) T i m khoAng cdch S1S2
b) Biet be rpng giao thoa do dxxac la 12,5 m m . T i m so v a n sang c6 tli(.
quan sat difoc t r e n m a n . Tdm tat
• 3 van sang lien tiep la 2 m m
-> 2i = 2 i = 1 m m
• D = 2 m
• X - 0,5 |am.
a) T i m a
b) L = 12,5 m m T i m N s = ?
llUdng dan gidi a) Khoang each S1S2.
. XD XD 0,5.10^2 1 = -> a = = —
2 i 1.10' a = 10 m = 1mm
b) T i m N ,
2i 2.1 [ l e = 0 , 2 5 So' v a n sang quan sat t r e n m a n
N , = 2k + 1 = 2.6 + 1 ^ Ns = 13 van saii.
B a i 2. H a i gUcfng ph^ng G i , G.2 dat sat nhau va nghieng v d i nhau mot gdc a = 2,57.10"'^ rad r a t nho. M o t khe S diWe r o i b^ng a n h sang don sac c6 buoc song X = 0,5 |.im dat song song v d i giao tuyen I ciia h a i gu'ong va each I mot doan d = 1 m. M o t m a n E song song true I va v d i S1S2 (vdi 8,82 la 2 anh cua khe S qua gtfong G i va G2) vk each I mot doan x' = 1 m. T i n h : a) Khoang v a n
b) 86' van sang c6 the quan sat diJorc t r e n m a n E.
Tom tdt
• a = 2,57.10"^ rad
• X - 0,5 f.im
• d = 1 m
• X = 1 m a) T i n h 1 b) N , = ?
Hiidng dan gidi
a) Khoang v a n i 1 = —
a
Vdi • a = 8,82 = 2d.a = 5,14.10"^ m
• D = H I + 10
H I H I
(1)
(2)
• X6t A S i H I 0.6: cosa =
S J S I
-> H I = SI.cosa = d.cosa x = d.cosa (3)
• 1 0 = x' (4) The (3), (4) vao (2)
S = X + x' = d.cosa + x' ~ d + x' (do a nho) ô 1 + 1 = 2 m 0,5.10 ".2 i a 0,194 m m
= 5.14,10' b ) N s = ?
• Be rong giao thoa thirdng
L = 2.x'.a = 2.1.2,57.10"^ = 5.14.10-'' (m) fk = 13 L 5,14.10-- ^
2i 2.0,194.10' le = 0,24
80 van sang N , = 2k + 1 = 2.13 + 1 -> N g = 27 v a n sang
BAI TAPTRAC NGHIfM
C a u 58. H a i guong ph^ng G i , G2 dat sat nhau va nghieng v 6 i nhau mot goc a = 3,57.10"^ rad. M o t khe hep S dirge r o i bang anh sang dcfn s^c c6 birdc song X = 0,5 (im, dat song song v d i giao tuyen (A) ciia h a i gu'ong va each (A) mot doan d = 1 m. M o t m a n quan sdt E song song vdi (A) va v6i S i , S2 ( S i va 82 la hai a n h cua khe S qua hai gUomg) va cdeh A mot doan x' = 1 m. T i n h khoang each giiJa h a i v a n sang lien tiep va so' van sang eo the quan sat diTdc t r e n m a n E.
A. 0,14 m m ; 51 van sang B. 0,14 m m ; 52 v a n sdng C. 0,15 m m ; 52 v a n sang D. 0,15 m m ; 51 v a n sang
C a u 59. Cho he hai gu'ong ph^ng G i , G2 hop v d i nhau mot goc a , gan b^ng I8O"
va mot nguon sang diem 8 chieu a n h sang dcfn sac vao m a t h a i giiong. Goi 81, 82 la a n h cua 8 tao bcfi h a i giTOng, m a n anh each ducfng t h ^ n g qua S ] , 82 mot khoang 2 m. Budc song a n h sang cua nguon S \k X = 0,5 (.im. Khoang van giao thoa t r e n m a n la i = 0,4 m m . H a y t i m khoang each 81, 82
A. 1,5 m m B. 2,5 m m C. 3,5 m m D. 4,5 m m
C a u 60. H a i gi/cfng ph^ng G j , G2 dat nghieng v d i nhau mpt goc r a t nho a = 4.10^^ rad, khoang each tCr giao tuyen I den m a n quan sdt E dSt song song vdri 81S2 (Si, 82 la anh eua 8 tao bcfi hai guong) bkng x' = 2 m va 81 = 1 m.
Bade sdng cua a n h sdng don s^c do S phat ra la = 0,6 (.im . T i n h khoang van va so van quan sat duorc t r e n m a n E.
A. 0,1225 m m ; 70 v a n sang B. 0,1225 m m ; 69 v a n sdng C. 0,225 m m ; 71 v a n sang D. 0,225 m m ; 70 v a n sdng