Hướng dẫn giải chi tiết đề thi tuyển sinh đại học, cao đẳng môn vật lí phần 2

ciidng do dong dien trong doan mach cung pha vdi dien ap giufa hai dau doan mach.. dien ap hieu dung giufa hai dau dien trcf thuan R nho hon dien ap hieu dung giufa hai dau doan mach..

DE THI TUYE

-Thdl gia

n la

m bai : 9

c = 3.10^m/s, d

o

Avogadro N

A = 6,02.102^mor\

V = 1,6.10~^^J

Cdu 1:

Cho phan uTng ha

t nhan |H+

|H ^ ^,He+

Qn + 17,6MeV Nan

A 5,03.10

" J B 4,24.10

^ J C 4,24.10

^ J D 4,24.10

\Mang

toa ra: E = N.17,6Me

V = 6,02.10'^

- 17,6.10^1,6.10"'

= 42,38.10'

° « 4,24.10"

J

Vay chgn dap an

h ciT

c da

i tre

g mac

h bkng:

10'^ 10"

C 4.10-'s

D 4.10-'s

Glai

Nang li/grng mac

h da

o dong:

2 2 1- 1

Chu k

i da

o dong: T = 27r>/L

C = 2

?:

^ = ^^"^"^^

= 4.10'(

Vay chgn dap an

D

Cdu 3:

T

ai mo

t

vi tr

i trong moi trifdn

g truye

n am, kh

m 1

0 B B gia

m d

i 1

0 B

C tang the

m 1

0 dB D gia

m d

i 1

0 dB

thdi diem t i mau chat phong xa X con l a i 20% h a t n h a n chtfa b i phan

ra Den thcfi diem t2 = t i + 100 (s) so h a t nhan X chtfa b i phan r a chi

con 5% so vdi so h a t nhan ban dau Chu k i ban ra ciia chat phong xa

Chia (2) cho (1) t a diXtfc: 2^ ^ = 4 - 2" => - ^ ^ = 2 « T = 50(s)

Vay chon dap an C

( j L i ) dufng yen Gia suf sau phan ufng t h u dUgfc h a i h a t giong nhau c6

cung dong nang va khong kem theo t i a y Biet nang liiofng toa ra cua

phan ufng la 17,4 MeV Dong nang ciia m5i hat sinh r a l a :

A 15,8 MeV B 19,0 MeV C 7,9 MeV D 9,5 MeV

Giai

Trong triTcfng hcfp khong k e m theo t i a y, theo dinh luat bao toan

nang Itfdng, tong dong nang cua hat sinh r a phai bfing nang lifcfng cua

Giai Chi tiet de thi TS DH, CD Won Vat If 85

phan ufng to

o do, ne

u go

i K

la

nang lufcfng cu

a m6i ha

t t

hi ta c6:

2K = 17,

4 MeV + 1,

6 MeV = 1

9 MeV ^ K = 9,

5 MeV

Vdy chgn dap an

D

Cdu 6:

Mot

hung day

in phSng de

t hin

ot tru

e do

i xufn

g nam trong

m

at phin

5 71

A

22 0V 2V

V D I

220^/2

Vdy chgn dap an

i 1

m can

g ngang, da

h vdr

i 4 bung song, B

ducfc

eoi la n

ut song To

e d

o truye

n son

g tre

n da

y la:

A 5

0 m/s •

B 2,

5 cm/s C 1

0 m/s D 2

o va

y tre

n da

y c

6 4 m

= 0

,5.2

0 = 10

(m/s)

Vdy chgn dap an

o photo

n m

a

nguon phat ra trong m

.10^^

86 Giai Ch

Giai

So photon ma nguon phat ra trong mot giay xap x i bang:

N = — = ~ - r « 3,02.10'^

hf 6.625.1(r'-'.5.10'-'

Vay chgii dap an C

Cdu 9: Theo thuyet luang tijf anh sang, phat bieu nao dvidi day la sai?

A Phan tijf, ngiiyen tuf phat xa hay hap t h u a n h sang, cung c6

nghia la chung phat xa hay hap thu photon

B A n h sang diioc tao thanh bdi cac h a t goi la photon

C Nang iLfgtng ciia cac photon anh sang la nhtf nhau, khong phu thuoc t a n so' ciia anh »ang

D Trong chan khong, cac photon bay doc theo tia sang vdi toe do

c = 3.10^m/s

Giai

Nang lifcJng cua cAc photon s = h f nen t a n so a n h sang khac nhau

thi nSng li/cfng e khac nhau

A ciidng do dong dien trong doan mach cung pha vdi dien ap giufa

hai dau doan mach

B dien ap hieu dung giufa hai dau dien trcf thuan R nho hon dien

ap hieu dung giufa hai dau doan mach

C cUdng do dong dien trong doan mach tr§ pha so vdri dien ap giufa hai dau doan mach

D dien ap hieu dung giffa hai dau dien t r d thuan R bang dien ap hieu dung giu:a hai dau doan mach

Cdu 11:

Trong scf d

o kh

h tac

h song

C Mac

h khuec

h dai D Anten

g v

6

tuyen,

kh on g

can

bo phan tach song

Vdy chon dap an

B

Cdu 12:

Song dien tCf

A

CO

than

trong

khong gian

D khon

g truye

n dtfcf

c tron

g cha

n khong

GiSi

Song dien tCr l

a son

g ngang, truye

vectcf E va

Vdy chgn dap an

B,

Cdu 13:

Mach dao don

n dun

g C dang thif

i thof

i diei

n t H

=VLC(u

u=

^-) B

i^

=^

{U

^u-\

)

C.i^

=LC(

U^

u^

) D

Giai

Ap dung din

a c6

:

-CU^

=-CU^

+lLi

^ oi^

=-(

u^

-ir)

Vdy chgn dap an

can bSng mot doar

A 4,

5 cm B 6

cm C 4

cm D 3

Cdu 16: Trong cac loai t i a : Rcfn-ghen, hong ngoai, tuf ngoai, dofn sac

mau luc; t i a c6 t a n so nho n h a t l a :

Ạ t i a hong ngoaị ' B t i a Rcfn-ghen;

C t i a dofn sAc mau luc D t i a tuf ngoaị

Giai

Tia hong ngoai c6 bifdc song Idn n h a t nen c6 t a n so nho nhat

Vay chgn dap an Ạ

Cdu 17: D ^ t dien ap xoay chieu vao hai dau doan mach gorh dien t r d

thuan 4 0 Q va t u dien mic n o i tiep Biet dien ap giufa hậdau doan

mach lech ph

Giai

Do lec

h pha: tanc

p

=

= tan-

o ^ = V3 « Z"

^ = RV3 = 40V3

Q)

Yay chon dap an

A • '

Cdu 18:

Hieu dien the giufa ha

' Hz

C 4,83.10'

^ Hz D 4,83.10'

^ Hz

Giai

Zc

Ta c6: e

U =

hf =

^ f-eU 1,6.10-".2.10'

= 4,83.10"

6,625.10-'-Vay chon dap an

(67rt-7rx

) (cm) (

x tin

h bSn

g met, t

A 3 m/s

B 6 m/s

C m/s 6 D

= 6(m/s)

Vay chon dap an

o tinh, Mo

y tinh C Th

o tinh D Tra

Giai

Trong so cac h a n h t i n h t h i Tho t i n h xa M a t Tro'i n h a t

Vay chgn dap an C

Cdu 21: K h i noi ve song am, phat bieu nao sau day la s a i ?

A Song am trong khong k h i la song ngang

B Song am truyen dxiac trong cac moi trUdng rAn, long va k h i

C Song a m trong khong k h i l a song doc

D d Cling mot n h i e t do, toe do truye n song a m trong k h o n g k h i

nho han toe do t r u y e n song a m trong nUdc

Giai

Song am t r o n g k h o n g k h i la song doc nen phat bieu A sai

Vay chgn dap an A

Cdu 22: Nguyen tijf h i d r o chuyen ttf t r a n g t h a i dUng c6 n a n g l u g n g

En = - l , 5 e V sang t r a n g t h a i dCfng c6 nSng liiong E m = -3,4eV Budtc

song cua bufe xa ma nguyen tiu hidro phat ra xap x i bkng:

Cdu 23: M o t con iSc 16 xo gom vien b i nho va 16 xo nhe c6 do cufng

lOON/m, dao dong dieu h6a vdfi bien do 0,1 m Mo'c the n a n g d v i t r i

can bang K h i v i e n b i each v i t r i can bSng 6 cm t h i dong nang cua eon

l^c bang:

A 0,64 J B 0,32 J C 3,2 m j D 6,4 m J

Giai

Ccf nang cua con l^c: W = ^ k A ^

The nSng cua con lac k h i each v i t r i can h^ng 6cm:

W = - k 6 1 0 - '

' 2

Dong nan

Wd =

W

Wt = -10

(10-')'-{6.10-')'

= 0.32J

Vay chgn dap an

B

Cdu 24:

DSt die

n a

p u = 220V2cosl007

tt (V) va

o ha

ai doa

n mach A

M v

a MB mSc no

i tie

n R mSc no

i tie

p vdf

i cuo

n ca

m thua

n L, doa

n C Bie

t die

ap

giufa ha

i da

u doa

n mach M

B c

6 gi

a tr

C 22

0 V

2 V

B

220

s D 22

0 V

V

AM

Giai

Diia vao d

e bai, t

0 (V)

Vay chqn dap an

i ca

n bkng

B va

i va

t d v

i t

ri ca

n bang

Vay chon dap an

B

Cdu 26:

M

ot lang kin

h thuy tin

, da

t tron

g

khong khi Chie

t sua

t cu

a lan

g kin

h do

i vd

i an

u mo

t chij

m tia sang son

g song, he

m va

o ma

t be

n eu

a lan

g kin

t nay Go

h xa

p x

i bang:

A 0,336° B

1,416°

C 13,312°

D 0,168°

92

Giai

Goc l e c h cua t i a s a n g do: D i = A(nd - 1) = 4(1,643 - 1) = 2,572°

Goc l e c h cua t i a s a n g t i m : Dg = A(nt - 1) = 4(1,685 - 1) = 2,74°

Goc l e c h giffa h a i t i a : A D = Dz - D i = 2,74 - 2,572 = 0,168°

Vay chgn dap an D

Cau 27: T a i m o t n o i t r e n m a t d a t , con lac dofn c6 c h i e u d a i C d a n g dao

dong d i e u h o a v d i c h u k i 2s K h i t a n g c h i e u d a i cua con iSc t h e m 2 1 c m

t h i chu k i dao d o n g d i e u h o a cua no l a 2,2s C h i e u d a i t b a n g :

cam L T a i t h d i d i e m d i e n a p giOra h a i d a u cuon c a m c6 do Idfn cifc d a i

Cucfng do d o n g d i e n c h a y qua cuon c a m : i = IQ COS

K h i u = UoCoscot = Uo t h i coscot = 1 K h i do cos

o r

a l

a 5

0 Hz S

A 16 B 8

C 4

D 12

Giai

Ta c6: 37

5 vong/phu

t = 6,25 vong/giay

n =

> p = — = =

Vay chgn dap an

B

Cdu 30:

H ie

c6 tin

h cha

t song

?

A Hie

n tMng

quang die

n trong

B Hie

n tiiofn

g quan

g die

n ngoai

C Hie

n ti/o'n

g quan

g pha

t quang

D Hie

n tiTdn

g

giao tho

a anh

sang

Giai

Hien tiiong gia

D

Cdu 31:

Chuyen dong ciia m

ot va

t l

a tong

A 1 m/s

l

Ta c6:

x, = 4sin

B 5 m/s

l

C 7 m/s^

D 0,7

Giai

= 4cosl0t(cm)

Hai da

o don

g x

i, X2

i + A2 =

7 (cm)

Gia toe cii

a vat: a

= x

" = -C O" A

cos (cot+ 9)

a ,„^

^ = co"A = 10".0,0

7 = 7(m/s")

Ydy chgn dap an

Cdu 32: Treo con \kc do'n vao t r a n mot oto t a i noi c6 gia toe trong

trUdng g = 9,8 m/s^ K h i oto dufhg yen t h i chu k i dao dong dieu hoa cua con lac la 2s Neu oto chuyen dong t h i n g nhanh dan deu tren diTcfng n&m

ngang v d i gia toe t h i chu k i dao dong dieu hoa cua con iSe xap x i bang:

Vdy chon dap an A

khe hep F cua mot may quang pho lang k i n h t h i t r e n t a m k i n h anh (hoac t a m k i n h mcj) ciia buong anh se t h u diroc:

A anh sang trSng

B bay vach sang tCf do den t i m , ngan each nhau hang nhOfng

khoang t o i

C eac vach mau sang, toi xen ke nhau

D mot dai c6 mau tCr do den t i m noi lien nhau mot each lien tuc

Giai

Tren t a m k i n h anh (hoac t a m k i n h mo') ciia buong anh se thu diio'e quang pho ciia anh sang trSng gom mot dai mau tCf do den t i m

Vdy chon dap an D

A Tia a la dong cac hat n h a n heli (^He)

B IChi di trong khong k h i , t i a a l a m ion hoa k h o n g k h i va m a t dan nang lUcfng

C K h i di qua dien trUcfng giijfa hai ban tu dien, t i a a bi lech ve phia ban am cua tu dien

D Tia a phong r a tCr hat n h a n v6'\e do bang 2000 m/s

Giai

Tia a phong ra tCr h a t nhan vdfi toe do bkng khoang 2.10'm/s

Vdy chon dap an D

t cu

a tia hong ngoai l

so Idn

hofn ta

n s

o cu

a anh sang do

so cu

a an

h san

g do

Vay chon dap an

B

Cdu 36:

M

ot va

an toe cii

a v

at ban

g 0 Ian dau

tien

or

thcfi diem:

i gia

n Iti

c va

t d v

i t

ri ca

n bln

g T

a c6:

+ Phi/tfn

g trin

h da

o dong: x = A cos (ot —

2)

+ Phi/On

g trin

h va

n toe: v = -co

A si

n

Khi

sin cot-

t (V) va

d R m^c no

t tre

A 2

A B

1

A ^ C

t A.

Cdu 38: Trong t h i nghiem Y-ang ve giao thoa anh sang, cac khe hep

Trong khoang giOfa hai diem M va N t r e n man or cung mot phia so vdi

van sang trung tam, each van trung tam Ian Itfgft 2mm va 4,5mm, quan

sat di/cfc:

A 2 van sang va 3 van t o i B 2 van sang va 1 van t o i

C 3 van sang va 2 van toi D 2 van sang va 2 van t o i

va 3,6mm) va 2 van toi (each van trung t a m 3mm va 4,2mm)

Vay chgn dap an D

Cdu 39: M o t dong ccf khong dong bo ba pha mac theo kieu h i n h r.ao

dUcfc noi vao mach dien ba pha c6 dien ap pha Upha = 220V Cong suat

dien cua dong cof la 6,6 V3 kW; he so cong suat cua dong ccf ia

Cif&ng do dong di$n hieu dung qua m6i cuon day cua dong ccf bang:

Cdu 40:

So vdi

hat nha

n ^^Si, ha

t nha

n ^Ca

c6 nhie

u hofn:

A 1

1 ncftro

n v

a 6 proton B

5 notron v

a 6 proton

C 5 ncftron v

a 1

2 proton D

6 notron v

a 5 proton

5 ncftron

Ha

t nha

n

2 0 c6 2

0 proton, 2

0 ncftron

Vdy chgn dap an

U oC

OS

cot + —

6 (V) va

n

c ot + -

12 (A

A 1

s cot +

D

= U

Q sin cot +

_ 27 1

Ta c6: ^ = tan

- =

Vdy chgn dap an

H

CD

Mon

Vatii ?

B Dien ap giuTa hai dau dien trof thuan sdm pha — so vdi dien ap

4 giOfa hai dau doan mach

C CiTcfng do dong dien qua doan mach scJm pha — so v d i dien ap

4 giOfa hai dau doan mach

D Dien ap giufa hai dau tu dien tre pha — so vdi dien ap giuTa hai

4 dau doan mach

G i a i

Phat bieu sai: "CiTdng do dong dien qua doan mach t r i pha — so

• • 4 vdfi dien ap giufa hai dau doan mach"

Vay chon dap an A

khoi liJcfng nghi bang 0 l a :

A pozitron B proton C ncftron D photon

G i a i Photon la hat scf cap c6 khoi Itfcfng nghi bang 0

Vay chgn dap an D

A phan ufng trong do mot hat nhan nang v9 thanh 2 manh nhe hom

B phan ufng hat nhan thu nang liTgrng

C. S L T ket hcfp hai hat nhan c6 so khoi trung b i n h tao t h a n h hat

nhan nang hon

D phan ufng hat nhan toa nang lUcfng

G i a i Phan ufng nhiet hach la phan ufng hat nhan toa nang lucfng

Vay chgn dap an D

khong doi va tu dien c6 dien dung C thay doi dtfofc K h i C = Ci t h i t a n

so dao dong rieng cua mach bkng 30 kHz va k h i C = C2 t h i t a n so dao

Giai Chi tiet de thi TS DH, CD M6n Vat li - 99

c c

do ng r ie ng cua m ac

h ba ng 4

0 kH

z

Ne

u C =

— t h

i ta

n s

o da

o

do ng r ie ng cua m ac

h ba ng :

A 1

0 kH

z B.'*IO

k Hz C 2

4 k Hz

i t hi

f, =

Kh

i C = C

'L

C, •

(v

di C =

+C , _

f,' + f^' =

' =

i > f =

yjf^+f^ =

= 5 0(

V30-+40-kz )

Vgy c/i on d dp

an D

Cdu 46: O

m at t ho an

g cu

a m ot c ha

t lo ng c6 h

ai ng uo

n ke

u h oa c un

g p ha v

di nh au v

a t he

o phiTdn

g t ha ng dufng

Bie

t

toe do t ru ye

n so ng k ho ng d

oi tr on

g qu

a t ri nh I an

ru ye

n tr en p ha

t r

a b an

g 1

2 c

m

Kh oa ng each n ga

n nh

at giuf

a h

ai

di em dao d on

g v6

i b ie

n d o

C LT C

d

ai na

m t re

n do an t ha ng A

B l

a:

A 6 c

m

B 1

2 e

m C 3

c

m

D 9 e

m

Gi

ai

Kh oa ng each giufa h

ai di em dao d on

g vd

i b ie

g ne

n M

- — = —

= 6(

cm

)

Vdy chon dap an

A

Cdu 47:

T ro ng t hi

gh ie

m Y- an

g v

e gia

o th oa a nh s an

g, ha

i k

he

di/gfc

ch ie

u sa ng d on

g thcf

i bd

i h.a

i buf

c xa d dn sac c

6 bud

c so ng I

n s

at c

6 v an s an

A.

2

3 B.

Giai Tai v i t r i 2 van sang trung nhau, ta c6:

\2X, =10?i, = > ^ = -

Vdy chgn dap an B , Cdu 48: M o t con iSc 16 xo dao dong dieu hoa vdi tan so 2fi Dong nang

cua con iSc bien thien tuan hoan theo th6i gian vdri tan so' £2 bkng:

A i

GiSi

V i chu k i cua dong nang bkng mot nufa chu k i cua dao dong nen

tan so dong nang gap 2 Ian tan so dao dong: fa = 2fo = 4fi

Vdy chgn dap an C

Cdu 49: Mot con iSc 16 xo gom vat nho va 16 xo nhe c6 do cufng

lOON/m Con l^c dao dong dieu h6a theo phifofng ngang vdi phiTcfng

trinh x = Acos((ot + (p) Moc the nkng t a i v i t r i can bang Khoang th6i

gian giufa hai Ian lien tiep con l&c c6 dong nang bang the nSng la 0,1s

Lay 71^ =10 Kho'i Itfgfng vat nho bang:

Cdu 50: M o t chat c6 kha nang phdt ra anh sdng phat quang vdfi birdrc

s6ng0,55^m K h i dung anh sang c6 birdc song nao dudi day de kich

thich t h i chat nay k h o n g the phat quang?

A 0,45 ^ m B 0,35 j^m C 0,50 ^ m D 0,60 ^im

G\k\i tiSt thi TS DH, CD M6n V^t If 101

Giai

Theo din

h lua

t Xtoc, an

t quang Tron

g ca

c hiidc

song tren

the pha

t quang

Vqy chon dap an

D

Cdu 51: Poloni ^^Po

phong x

a a va bien ddi than

h ch

i Pb Bie

t kho

i

lUcfng ca

c ha

t nha

n Po

; u; P

b Ian

\\iat

la: 209,937303u

A 59,2

0 MeV B 29,6

0 MeV

C 5,9

2 MeV D 2,9

6 MeV

Giai

Do hu

t khoi: A

m = mp^ -

(n^P

b + )

= 209,937303U

- 205,929442

u -4,001506

u = 0,006355u

AE = Am.c'=5,919682

5 « 5,92 MeV

Vay chgn dap an

C

Cdu 52:

Mpt scfi da

y chie

u da

i i

cSng ngang,

ha

i da

u c

o dinh Tre

g vo

i n bung song, to

e d

o truye

g th

5^.

C

^ D

hi = -

V

nv

Khoang thcfi gia

n giuf

a ha

i Ia

n lie

D

Cdu 53: K h i vat r a n quay bien doi deu quanh mot true co d i n h t h i

A gia toe goe eua vat khong doi

B tdng roomen eua eae ngoai life tac dung len vat doi vdti true nay

C gia toe toan phan eua mot diem t r e n vat luon khong doi

D toe do goe eua vat khong doi

Giai

K h i vat ran quay bien doi deu quanh mot true eo d i n h t h i gia toe

Vay choii dap an A

hinh may v6 tuyen, 16 siTofi dien, 16 v i song; nguon phat r a t i a tuf ngoai manh nhat la

A ho quang dien B 16 v i song

C man h i n h may v6 tuyen D 16 sirdi dien

Giai

Vat or nhiet do eao hcfn se phat ra nhieu t i a tuf ngoai hcfn Trong

cac nguon bufe xa t r e n t h i ho quang dien d nhiet do eao nhat

Vay chgn dap an A

10 rad/s t h i h i h a m Banh xe quay eham dan deu, sau 5 s ke tCf liic

A 2 r a d / s l B 0,2rad/sl C 50rad/sl D 0,5rad/sl

Gi^i

Gia toe goe: y = -^ = = - 2 rad/s^

V i xet ve do Idrn nen ta ehon gia t r i 2 rad/s^

Vay chgn dap an A

cuon earn thuan mae noi tie'p vdri mot bien t r d R l?ng v d i h a i giA t r i

Ri = 20 Q va R2 = 80 Q eua bien t r d t h i cong suat tieu t h u t r o n g

doan maeh deu bang 400 W Gia t r i eua U l a :

A 400 V B 200 V C 100 V2 V D 100 V

Giii Chi l\6t 06 thi TS DH, CD M6n V$t li 1 03

20'+Zl SO + Zl

« 2 0 '

4 + 4 Z'

^

= 8

0 + Z'L

« 3 Z [ •

= 4 80

0 ZL = 40 (Q )

^ P(Rf+

zM

4 00 (4 00 + 16 00 ) , ,

Ta co :

U ' - -

^

^

^ ^ = ^

= 40 00

0

=^

U = 2

00

(V

Vay chgn dap an

A.

!

B.

'i C.

l.

D l

Giai

Goi V 1^ va

n to

e cu

a vSt , V

Khi V = 50%v

^ =

, ,

,r

— = ^ =

W « mv^

4

• ~

2~

Vdy chgn dap an

i lie

n h

e giO:

a Wa , I

va L la:

A W , =

—

B W

d =

21.V C

W , =

ia ic hi ti gt d^

th iT SO

Giai

Dong nang quay: Wa = — I©'

Vdy chon dap an C

Cdu 59: Mot dong ho chuyen dong thing deu v6i toe do v = 0,8c (vdfi e

la toe do anh sang trong chan khong) Sau 12 phut (tinh theo dong ho

yen la:

ThcJi gian chay cham hofn: t = At-Atg = 20 - 12 = 8 (phut)

Vdy chgn dap an C

Cdu 60: Mot con \Ac vat li la m6t vat r^n c6 khoi lilgrng m = 4 kg dao

den true quay cua no la d = 20 cm Lay g = 10 m/s^ va =10 Momen

quan tinh cua vat doi v6i true quay la:

DE THI TUYE

dl A

Thdi gla

n la

m bai : 9

; d

o \6n

dien tich

nguyen

to e = 1,6.10"^^C

; to

e d

o an

h san

g tron

g eha

n khon

g e =

S.l

OW

s;

lu = 931,

5 MeV/c

p hu cf ng

truyen song ma dao don

g ca

truyen trong chat lon

g luo

n la son

g ngang

la son

g doe

D Bu6c

song la khoang

each

giOTa

hai die

m tren cung mot

phiiofng

truyen song ma dao don

Glai

Bu'd'c song

l a

khoang each

n gS n

phtTOng

truyen

song Vqy chon dap

ft (U khong

dci, ta

g vk

dung khan

i tan

= i f l B

f2

=—

fl s

C.

f2

= -f

<=>f, =

Vdy chgn dap an

Cdu 3: Gia sijf t r o i i g m o t p h a n ufng h a t n h a n , t o n g k h o i liJOng c u a c a c

A t o a n a n g l i / o n g 1,863 MeV B t h u n a n g liTcfng 1,863 MeV

C t o a n a n g liicfng 18,63 MeV D t h u n a n g liTcfng 18,63 MeV

Vdy chon dap an D

Cdu 4: Trong mach dao dong LC 11 tifdng dang c6 dao dong dien t\I t i i

de dien tich tren tu giam tCr gia t r i ciic dai xuong con mot nufa gia t r i

Thdi gian nang liicfng dien giam tCf ctfc dai xuong mot nufa bang

thdi gian q giam tCr QQ —> : ' •

Vdy chon dap an A

Cdu 5:

C ha

t ph on

g xa p ol on

i g°P

o ph

at ra t ia

a va b ie

Ch

o ch

u

ki ba

n ra cua '^°Po la 138 n ga

y

Ba

n da

u po lo

ni ng uy en c ha

t

Ta

i thof

i di em t

ni va

so ha

t nh an c

hi tr on

g mku

la T

ai thcf

i di em t2 =

ti

+ 27

6

ng ay , ti

so giuf

a s

o ha

t n ha

n po lo

ni va

so ha

t n ha

n ch

i t ro ng

,

1 50

% 50

% 1:1

2 25

% 75

% 1:3

3 12,5%

87 ,5

% 1:7

4 6,25%

93 ,7 5%

1:15

Dii

a va

c ba ng suy r

a ti = 2T = 27

6 ng ay v

a = 4

a 1:15

Vay chgn dap an

D

Cdu 6:

M

ot ch

at di em dao do ng d ie

u ho

a tr en t ru

e Ox Kh

i c an b an

g th

i to

e d

o cu

a no la 20 cm/s

Kh

i c ha

i g ia toe cu

Bi

en

do

dao do ng cua c ha

t di em l a:

A 4 c

m

B 5 c

m C 8

(V,,CBU

= = 20

= 40V

3 cm/s

^

(1) (2)

Th ay (1) va

o (2 ) su

y ra : c

o =

4 (rad/s ) A

= 5cm

Vay chgn dap an

B

Cdu 7:

M

ot kh un

g da

y dfi

n ph

^n

g qua

y de

u vd

CO

d in

h na

m tr on

g ma

t ph dn

g kh un

g da

y, tr on

u c

o veetc

f ca

m ufn

g tC

f v uo ng goc vdf

i tr ue q ua

K

Suat dien dong cam ufng trong khung c6 bieu thuTc e = Eocos(cot +

Tai thori diem t = 0, vecto phap tuyen cua mat phang khung day hop

vdi vectof cam ufng tii mot goc bSng

A 150° B 90° C 45° D 180°

Giai

Vi pha ban dau tCf thong nhanh htfn pha ban dau suat dien dong

motgoc nen ( ( P o ) ^ = ( ( P o ) _ ^ + ^ = 7r

Vdy chon dap an D

Cau 8: Khi noi ve mot vat dao dong dieu hoa, phat bieu nao sau day sai?

A Ccr nang cua vat bien thien tuan hoan theo thdi gian

B Life keo ve tac dung len vat bien thien dieu hoa theo thofi gian

C Van toe cua vat bien thien dieu hoa theo thcfi gian

D Dong nang cua vat bien thien tuan hoan theo thcfi gian

Giai

Trong dieu kien \i tUo'ng, cd nang khong thay doi theo thcfi gian;

trong dieu kien khong \i tudng, cof nang giam dan theo thdi gian

Vay chgn dap an A

Cau 9: Mot doan mach AB gom hai doan mach A M va M B mic noi

tiep Doan mach A M gom dien t r d thuan R i mac noi tiep vdfi tu dien

vdri cuon cam thuan c6 do tiX cam L Dat dien ap xoay chieu c6 tan so

va gia t r i hieu dung khong doi vao hai dau doan mach A B K h i do

doan mach AB tieu thu cong suat bkng 120 W va c6 he so cong suat

bang 1 Neu noi tat hai dau tu dien t h i dien ap giufa hai dau doan

mach A M va M B c6 cung gia t r i hieu dung nhifng lech pha nhau ^ ,

cong suat tieu thu tren doan mach AB trong tnTdng hcfp nay bang:

Sau kh

i noi

ta

t th

va L; M

n tar

n gia

c AMB can su

U CO

S (

Lay (2) chi

a ch

o (1) t

a c6: P = cos

Vay chgn dap an

n kin

h l

a r = 2,12.10"^°m Qu

C O

D L

Vgy chgn dap an

D

Cdu 11:

Ban mot proto

h the

o do 'n v

c i

D 4

Giai

Dau hieu nhan dang: 2

hat X(He) c

He = m pV

Cdu 12: M o t l a n g k i n h c6 goc chiet quang A = 6° (coi la goc nho) dtfcfc

dat trong khong k h i Chieu mot chum a n h sang trSng song song, hep

vao mat ben cua lang k i n h theo phifcng vuong goc vdi m a t phang phan

giac cua goc chiet quang, r a t gan canh cua lang k i n h D a t mot m a n E

sau lang k i n h , vuong goc vdi phucfng cua chCim t i a t<Ji va each m a t

phang phan giac cua goc chiet quang 1,2 m Chiet suat cua l a n g k i n h

Do rong ti^ mau do den mau t i m cua quang pho l i e n tuc quan sat dUdc

sic mau lam ta quan sat difofc he van giao thoa t r e n m a n Neu thay

anh sang dcfn sic mau lam bang anh sang dan sac mau vang va cac

dieu k i e n khac ciia t h i nghiem dtrgfc giiif nguyen t h i

A khoang v a n k h o n g thay doi B v i t r i v a n t r u n g t a m thay doi

C khoang van t a n g len D khoang v a n giam xuong

lam

-Vay chgn dap an C

Cdu 14: Doan mach A B gom hai doan mach A M va M B mac n o i tiep

471 • •

mac r o i tiep voi cuon cam t h u a n Dat vao A, B dien ap xoay chieu c6

gia t r i hieu dung va t a n so k h o n g doi t h i dien ap tufc thcfi of h a i dau

111

do an m ac

h A

M v

a M

B I an

\\iat

l a:

UA

M = 50>y2

co

sf 10

0;

rt

- —

U|^B = 150cosl007rt

(V )

He

so co ng s ua

t cii

a d oa

n ma ch A

Ta c6:

B

0, 71

C 0,95

D 0,86

9i

0-= -

U^B

= UI

M +U

L + 2U ,^

.U MB CO S^

= 10 4,8

U^ecoscp = U^^

, -coscp^^

, +

U^3Cos

(p^,B ^ cosc

p = 0,84

Vay chon dap an

A

Cau 15:

M ot c ha

t d ie

h ba ng c m; t t in

h bk ng s)

Ke t

tf t = 0 , c ha

t di em d

i q ua

ai th

di di em :

A 30 16

s

B

30 15

s C 603

0 s

D

60 31

s

Giai

Nhdn xet:

Q ua

y mo

t v on

g c

6 2 I an c an t im

g tho'

i va

t t rd ve d un

g v

i t

ri bi en b an

hi va

t d

i t he

m m ot I an njjfa

Va

y to ng go

c qu

> t = 30 16 (s )

Vay chqn dap an

A

Cdu 16:

T he

o th uy

et ti/cfn

g doi,

m ot e le ct ro

n c

6 do ng n an

hi cu

a n

o t

hi ele ct ro

n n ay c hu ye

n d on

B

2, 24 1 0V

s

C 1, 67 l OW

s ' D

2, 75 1 0W

s

Giai

Ta co : Wd = E -E o=

^ Eo

2 -i

= -moc' « v = 2,24.10'm/s

1

-Vdy chgn dap an B

Cdu 17: Mot con lit dan difcfc treo vao tran mot thang may Khi thang

may chuyen dong thang dufng di len nhanh dan deu vdi gia toe c6 do Idfn a thi chu k i dao dong dieu hoa cua con lac la 2,52s Khi thang may chuyen dong thing dufng di len cham dan deu vdri gia toe eung c6 do Idn a thi chu k i dao dong dieu hoa cua eon l i e la 3,15s Khi thang may dufng yen thi chu k i dao dong dieu hoa cua con l&c la:

Cdu 18: Mot chat phat quang diicfc kich thich bang anh sang c6 bifdc

song 0,26 |am thi phat ra ^nh sang c6 btfdc song 0,52 ^ m Gia suf cong

suat cua chum sang phat quang hkng 20% cong suat cua chum sdng

kich thich Ti so giufa so photon anh sang phat quang va so photon anh sang kich thich trong cung mot khoang thoi gian la:

10"

Giai

Cong thufe anh sang kich thich: P^., = N he

he = n : P t quang g pha h san an thufc Cong

Suyr

a H =

t Trcfi, pha

n cu

a h

e Ma

t Trcfi

B Ca

c hanh tin

h ga

n Ma

t Trcf

i nha

t l

a Thu

y tin

h

D Hanh tin

n Vifc^n

g tin

h •

Giai

Thie

n vLfcfn

g tin

h khon

g pha

i l

a han

h tin

h x

a m

at trcf

i nhat

Vdy chon dap an

k

hi mo

t chu

m tia sang son

r mo

t tia sang) go

m 5 thanh phan don sSc:

tim, lam

, do

,

luc, vang

Tia

16 dcf

n sic mau luc d

i l

a l

a ma

i m

oi trifofng) Khon

g k

e tia do'n sac ma

u luc, ca

g k

hi l

a ca

c tia dcfn sSc ma

u

A lam, tim B do

, vang, lam

C ti

m, lam, do D do

, vang

Giai

Dieu kien

va sinigh = — nen: n

(igh)d6 > - (igh)luc >

- (igh)ti

m

Vay tia

do v

a tia vang khong

do v

a tia vang

bi ta

Vdy chgn dap an

D

Cdu 21:

Nguyen tac hoa

o

A hie

n tiicfn

g quan

g die

n trong

B hie

C hie

n ttrgn

g quan

g die

n ngoai

D hie

n tUcfn

g tan sac an

h sang

Giai

Nguyen tac hoat dong cua quang dien t r d diTa vao hien tiidng quang dien trong

Dap an dung Id A

Cdu 22: Dat dien ap xoay chieu u = Uocoscot (Uo khong doi va co thay

doi diitfc) vao hai dau doan mach gom dien t r d thuan R, cuon cam thuan

CO do t i i cam L va tu dien c6 dien dung C mSc noi tiep, vdri CR^ < 2L

Khi 0) = coi (0 = 0)2 t h i dien ap hieu dung giOfa hai ban tu dien c6

cung mot gia t r i K h i co = COQ t h i dien ap hieu dung giufa hai ban tu

dien dat cifc dai He thufc Hen he giufa coi, CO2 va coo la:

COn

1 1 vco- co;^

M a t khac (Uc)max theo co k h i <=> COQ = • ,

hi electro

n

chuyen tiT quy dao

X,

2 1 ^

0

^

0

he ^ ^ E

(1)

(2)

La

y (1) chi

a ch

o (2) t

a c6:

C

Cdu 24:

Neu noi ha

i tie

p

v6i die

n trd thuan

R = 1

g d

o I Dun

oi nguo

n ro

Q C 0,5Q

D

^r = ^-R = lQ

Vdy chgn dap an

A

11

6 Giai Ch

i fiS

t th

i TS D

H,

CO

M6n

Vat I

Cdu 25: Trong thi nghiem Y-ang ve giao thoa dnh sdng, hai khe diitfc chieu hkng anh sang dcfn sac, khoang each gida hai khe la 0,6 mm

Khoang van tren man quan sat do dirgfc la 1 mm TCr vi t r i ban dau,

neu tinh tien man quan sat mot doan 25 cm lai gan mat phing chiifa

hai khe thi khoang van mdri tren m^n la 0,8 mm B\X6c song cua anh

sang dung trong thi nghiem la:

Cdu 26: Mot mach dao dong LC l i tiiorng gom cuon cam thuan c6 do tU

cam 50 mH va tu dien c6 dien dung C Trong mach dang c6 dao dong

dien tii tU do vdri ciromg do dong dien i = 0,12cos2000t (i tinh bang A, t tinh hkng s) O th6i diem ma ciXbng do dong dien trong mach bkng

mot nufa cUong do hieu dung thi hieu dien the giufa hai ban tu c6 dp

Cdu 27: Phat bieu nao sau day la sai khi noi ve song dien tijf?

A Trong s6ng dien tCr t h i dao dong cua dien triTcfng va cua tii

trifdng tai mot diem luon dong pha viJi nhau

B Song dien tii la song ngang nen no chi truyen diicfc trong chat rhn

c6 the bi phan xa va khuc xa

D Song dien tCf truyen diigrc trong chan khong

C LT C

2 cm C 5,

7 cm D 2,

v^a x

= Ac

o =

A, 2m

i gia

n da

o don

g la:

4 4o)'

gian nay, m

2 d

i difgrc :

s =

v A

t = v^^.At =

oA.—

w

71.2 V

2 cm

a).2V

2

Khi d

o k ho an

d =

s -A

'«

3,

2 (c m)

Vay chgn dap an

Cdu 29: Dao dong cua mot chat diem c6 khoi ItfcJng 100 g la tong htfp

cua hai dao dong dieu hoa cung phUofng, c6 phiicfng trinh l i do Ian Itftft

la Xi = ScoslOt va X2 = lOcoslOt vxi va X2 tinh bang c m , t tinh bkng s)

Moc the nang or vi t r i can bang Ccf nang cua chat diem bkng:

Cdu 30: Lan lifcft dat cac dien ap xoay chieu u i = U cos(1007it + 9 1);

mach gom dien trd thuan R, cuon c%m thuan co do tiT cam L va tu dien

CO dien dung C mSc noi tiep thi ciTcfng do dong dien trong doan mach

CO bieu thufc tufctog ufng la: i i = IV2 coslOO;tt; i2 = IV2 cos(1207tt + ^ )

h l

a U

A = U

B = acosSOTit

iv6i t

tinh bang s) To

m M

or ma

t cha

t lon

g nk

cm C 2

V2cm, D

2Vi0

; U

Q = 2acos(507rt-97c)

2k7i=>d = 9-2k>

AO = 9^

i k

^ax =

-1 , su

y ra

dmin = 11

= 2710

Vdy chgn dap an

m nut, B la mot die

m bun

g ga

n A nhat, C

la

trun

t khoan

g thd

i Ian ma l

n da

y la

:

A 0,25m/s B

0,5m/s C

2 m/s D 1

m/s

Giai

Ta c6 bie

X vdi

12

0

Gilii ch

r t ig td

S th

i T

S BH

- Bieii do song t a i diem B

Vi GO the coi diem B nhtf mot chat diem

dao dong dieu hoa vori bien do A B , t h i thdi

gian ngan nhat giOfa hai Ian diem B c6 l i do

Vgy chon dap an B

Cdu 33: M o t nguon diem O phat song am c6 cong suat khong doi trong

mot moi trifdng truyen am dang hifdng va khong hap thu am Hai

diem A, B each nguon am Ian Ixiat la ri va r2 Biet ci^cfng do am tai A

gap 4 Ian ci/&ng do am tai B T i so — bang:

2

4 Giai

Ap dung cong thufc

Vdy chon dap an A

Cdu 34: Dat dien ap u = UV2 coscot vao hai dau mot tu dien t h i cUcfng

do dong dien qua no c6 gia t r i hieu dung la I Tai thoi diem t, dien ap

qua

no l

a i

He

thijfc lie

n

he giiJa ca

c d

ai lu"crn

g l a:

2

-2 1 " > -

a i n en

giOfa chun

g luo n

c6

mot cong thuTc do

Vdy chgn dap an

o sc

f sua

t

nen cuon

thuT

cap b

so die

n a

p ban

g 0,45 B

o qu

a mo

i

hao ph

i trong may bien

ap D

e disac

may bien ap diing nhi

m va

o cuo

n thu

f cap:

A 10

0 von

g day B 8

4 von

g day

C 6

0 von

g day D 4

0 von

g day

Gihi

Goi Ni

, N 2

m

N N +

0,45 N, =

Vdy chgn dap an

C

122 GiaJchitietdethiTSDH,CDM6nVatl

i

Cdu 36: D a t dien ap xoay chieu u = u V 2 c o s l 0 0 7 i t vao h a i dau doan

mach m^c noi tiep gom dien trd t h u a n R, t u dien c6 dien dung C va

cuon cam t h u a n c6 do tiX cam L thay doi difcfc Dieu c h i n h L de dien ap

dai do bkng 100 V va dien ap hieu dung d hai dau t u dien bang 36 V Gia t r i cua U la:

A 64 V B 80 V C 48 V D 136 V

G i a t

K h i dieu chinh L de dien ap hieu dung of hai dau cuon cam dat gia

chat diem trong khoang thcfi gian ngan n h a t k h i chat diem d i tCf v i t r i

the nang la:

A 26,12 cm/s B 21,96 em/s

C 7,32 cm/s D 14,64 em/s

G i a i

T h d i gian ng^n n h a t vat d i tCf v i t r i c6

dong nang b^ng 3 Ian the nang de'n v i t r i

ta CO the bieu dien nhiT t r e n h i n h ben