Luyện thi cấp tốc các dạng bài tập từ các đề thi quốc gia môn vật lý (NXB đại học sư phạm 2011) phạm đức cường phần 3

Song v6 tuyin c6 buac song Ian hom 3000 m dupe dung trong thong tin lien dual nuac.. Sy phat song di?n tu khong dya vao hi^n tupng cpng huong di^n tu.. khong xay ra khi chieu chum anh sa

u 14 ) C

1 Z

Do CO =

Kh

i K dong m^ich c

hi c

6 R I

i = —

R

Kh

i K ng3t m^ic

h go

m R n

oi tie p

X =>

I2 = — (

Z l

a t6n

g t ra ciia m^ich)

Z

Theo de bai li = I2 =

> R = Z N hu v^y c

hi c

6 da

p a

n C thoa man dieu

Ca

u 17 )

A

Kh

i C = C

n =>c

o = J—

=>

f

=6 0H

Ca

u 18 ) B

n, U, ^

100

U2

=5 0V

n,

U

2 U2

Ca

u 19 ) A C au 20) A C au 21)

A

Ca

u 22 ) D C

au 23) B

Ca

u 24 )

hin chin

h l

a nSn

g lu

Q = W

au 26) B C

au 27) D C

au 28) C

Ca

u 29 ) A C au 30) A C au 31) C

Ca

u 32 ) D

he

Tir A = —

{XQ l

a gi

m lo^ii ) =

5 ur

n ; >toAi = 0,36

Ca

u 33 )

A

Kh iB co dj nh : U 5

|

Kh iB tv do :l = m -(

m=

1,3, 5,

Theo de bai ta co 5—

Cau34)A

Theo du ki?n bai toan, ta c6: ^ = ilE + E j i ; i}£ = ] ^ +

Do Xi > A.2 Eao2 > E<ioi V a y dpng n^ng Ian nhat ma electron k h i burc ra k h o i

NSng lugrng lien ket cua h^t nhan Heli AWik = Am.c^ ( A m ) dp hyt khoi cua He)

N i n g lugrng lien ket rieng cua Heli la AWikr = ^ = 7 , l M e V

Khoi lu(7ngNatri con l ^ i sau 2 nam: m = — ^ = 1,7

=> So h^t Natri con l?ii sau 2 nSm l a N = ^'^"^'^"^"^^—

t = 1 0 0 4 T + — T = 20,088 s

12

201

u 42 ) D Ca

u 43 ) B

Do U AN vuong pha v

ai UA

i i =>

cupn day c6

di?n tra

Theo gian do vecta:

UN

B

= -

^

^ = 200

V , 0

cos60

Ca

u 44 ) D

Ta c6: eU , =

Eai; eU

2 = E<j2 =

> U

2 = 4

Ui

(v

j = 2vi ne n

Ed2 =

4En)

Ca

u 45 ) B

Kh

oi lugrn

g co

n l^

i l

a m'

=

« x

> 2

= -

> ni

g = 16

g

2T 2

^

Ca

u 46 ) D C

au 47) C C

au 48) D

Ca

u 49 ) A

cm

=> L vc ho ip hy cc od pl on |F| = k

i O la van t

oi thu

r 3 (ti'nh tir va

djch chuyen

i y la dp djch c hu yi

n cu

a ngu6

n S )

Ca

u 51 ) C

=>G6c quay dupe la

a = — = 150 rad

2y

Ca

u 52 )

(0^

Tirco = y t=

>t = 0,25

s

Ca

u 53 ) C Ca

u 54 ) A

Chpn tryc qiiay

di qu

a C va vuong goc v

ai thanh

, nkm

trong mat phSn

g vuong

l

goc hinh

^ ^ l

o = l

o ^ m CG

^ CG = ^ = ^

202

Ciiu 55) A

1 T A Thai gian di do^n x bing — = — =:> x = —

-Cau 58) A

Cau 59)A

Dpng nang cvrc d^i ciia cac quang electron khi thoat ra khoi catot la:

A

electron khi den anot)

Cau 60) C

203

ON LUYEN

Cau 1) Co

e cSn

g da

y tSn

g dan

vao

v$t

Cau 2) V^

c o, co thai gian

0 N/

m tre

o than

g dung, d§

sl

A 12N

B.

16

N C

ION D 14N

Cau 5) Mp

^ , 92 CO

gia trj bang:

A

^ B

^ C D

Cau 6) Co

0 g treo thang durng

dao

dpng

dieu h6a t^i na

a bien tra

u d

o gi

S

nguyen gia trj

R o v

a tha

y do

i C den gia trj

W C

400W

D 20

0 W

204

Cau 8) T^i diem S tren m^t nuac yen tinh c6 nguon dao dgng di§u hoa theo

phuang thSng dung vai tin so 50 Hz Khi do tren m$t nuac hinh thanh mgt h? song tron dong tarn S T^i hai diem M , N nim each nhau 9 cm tren duang thing

di qua S luon dao dpng cung pha vai nhau Biet ring, toe dp song c6 gia trj xac djnh tu 70 cm/s den 80 cm/s Toe dp truyen song tren m$t nuac la

A 70 cm/s B 72 cm/s B 80 cm/s D 75 cm/s

Cau 9) Chpn phat bieu sai:

A Cac d?ic trung sinh li ciia am gom c6 dp cao, dp to va am sic

B Dp cao cua am chi ph\ thupc vao tan so am

C Dp to cua am chi phy thupc vao tan so am

D Nguang dau hau nhu khong phy thupc vao t i n so am thanh

va B CO tan so 50 Hz T^i d i l m M each A va B la di = 19 cm va d2 = 21 cm dao

dpng vai bien dp c\rc d^i Cho biet giua M va duang trung tryc cua A B khong

CO eye d^ii nao khac Toe dp truyen song bSng

A 10 m/s B 100 cm/s C 10 m/s D 100 m/s

Cau 11) Khi c6 hifn tupng song dCmg tren mpt day dan hoi, hai diem byng doi

xung nhau qua mpt nut s6 dao dpng

A ciing pha B ngupc pha C vuong pha D l?ch pha 45°

Cau 12) Trong m^ich dao dpng LC l i tuang, nhung d^i lupng bien thien cimg pha

la

A dif n tich q ciia ty va di?n ap u gifta hai dau ty dif n

B cuang dp dong di^n i qua cupn cam va dif n ap u ciia ty di^n

C difn tich q cua ty va cuang dp dong di?n i qua cupn cam

D cuang dp dong di$n i qua cupn cam va dif n ap a hai dau cupn cam

Cau 13) M^ich dao dpng LC If tuang dupe diing lam mgch chpn song ciia may thu

thanh May thu dupe song v6 tuyen c6 buac song la 60 m Ghep them ty di^n c6 di?n dung Co = 4C noi tiep vai C thi may se thu dupe song v6 tuyen c6 buac song:

A 75 m B 4 8 m C 120 m D 53,7 m

Cau 14) Chpn phat bieu sai:

A Song v6 tuyin c6 buac song Ian hom 3000 m dupe dung trong thong tin lien dual nuac

B Anten la mpt m^ch dao dpng ha

C Nguyen tic thu song di?n tu dya vao hi?n tupng cpng huong difn tu

D Sy phat song di?n tu khong dya vao hi^n tupng cpng huong di^n tu

Cau 15) Chpn phat bieu sai Song di?n tir

A khi di tir khong khi vao nuac se doi phuang truyen

B CO toe dp nhu nhau trong mpi moi truang

C la song ngang

D truyen dupe trong chan khong

205

Cau 16)

y de

u va

i to

e dp goc 3000 vong/phiit quan

B (B c6 dp Ian 0,02

n d

g sua

t di?n dgng xuat hi?n trong khung bSng

n sof Tha

y do

i R d

e n

giatri R ot hi UL ma x'l uc

do

A R 0- 2O

D

R„

^

L2 7i f- - C27;f

Cau 18) Mp

i cuan

g d

p don

g di?n qua

m^ch la

i = Iocos(cot +

B go

m c

6

A R va

L B L

va

C

C R va

C D khon

g xa

c djn

h dugc

Cau 19) D

cu

a

day tai di?

0 V C 22

0 V D

II

OV

Cau 20) Tron

0

B bang nha

D khon

g the bang nhau

Cau 21) Ma

y pha

t di

?n xoay chieu mgt ph

cam img di?n ti

206

B

Cau 22) Do^n m^ch di?n nhir hinh ve D^t

vao hai dau do^n m^ch mpt di?n ap xoay

chieu u = 100V2cos(1007rt + ^ ) V thi ^

dong di?n qua m^ch ch^m pha so vai

di?n ap hai dau m^ch., Thay von ke (V) bang ampe ke c6 di?n tra khong dang

ke thi dong di^n qua m^ch c6 gia trj hifu dyng la 2 A Biet von ke c6 di?n tra

v6 cung Ian va cupn day c6 dp ty cam L = — H Di?n tra ho^t dgng ciia cupn

noi ti^p mpt di?n ap xoay chieu c6 tan so 50 Hz on djnh Khi thay doi R den gia

trj Ro = 100 Q thi cong suit tieu thy tren di^n tra d^t gia trj eye d^i Biet cupn

day CO dp ty cam L = — H, di?n tra trong r = 60 Q Di$n dung ciia ty c6 gia trj

271 bang

Cau 24) Cho m^ch di?n A B gom mpt di?n tra thuan R = 27,5 n, mpt ty di^n c6

di^n dung C = ^ ^ ^ F , mpt cupn day c6 dp ty cam L = — H va c6 di^n tra

67t 4n

thuan r = 22,5 fi Cac phan tOr tren dupe mSc noi tiep vai nhau D^t vao A, B c6

mpt di^n ap xoay chieu u thi di^n ap giira hai ban ty di?n c6 bieu thuc u^ =

160cos(1207rt ) (V) Bieuthuc cua di^n ap u la

Cau 25) Hi^n tupmg tac sSc

A chi xay ra khi chieu chum anh sang trSng h^p qua iSng kinh

B xay ra khi chieu chum anh sang dan sSc bat ki qua lang kinh

C khong xay ra khi chieu chum anh sang h^p qua ban hai m$t song song lam

bang chat trong suot

D xay ra khi chieu xien goc chum anh sang h^p, khong don sSc tir khong khi

vao moi trucmg trong suot bat kl

207

Cau 26) Mp

c t^

o bo

i

tia 16 mau do va mau tim

la

A 45

° B 60

° C 15

° D 75

°

Cau 27) Tron

n san

g trun

g tam) v

a va

n san

g b^

c 3 gan nhau nhat ban

g 2,

5 m

m

Khoang each tir ha

, 2 mm C 0,

6 mm D 2

mm

Cau 28) Chie

g ^c kieh thich phat sang) Tre

C ca

c v^c

h do, lam, cham, ti

Cau 29) Son

i am

Cau 30) Di?

o qu

a dpn

g

nSng ciia

e kh

i r

a kho

i catot Bua

6 p

m D 25,

6 A

°

Cau 31) Ch

" m

; r

3 = 84,8

lO

" m Nguye

2 C r

j D r

, ho$

c

Cau 32) Do^

t va

o ha

i diu do^n m^ch mpt di?

n •

^

— •

ap mpt chie

u khon

g doi Chie

u va

o quan

g tr

a ^ ^

anh sang c6 buac song nho han giai h^

n quan

g di

f n trong ciia chat ba

n da

n l

a m

quang tra D

208

Cau 33) Tia Laze

A khong CO tinh dom s4c cao

B gom cac photon c6 cung tan so va cung pha

C khong truyen duQfC trong chan khong

D dam xuyen m^inh vi c6 buac song ngin nhu tia tir ngo^i

Cau 34) Phat bieu nao sau day sai?

A Huynh quang la s\ phat quang c6 thai gian phat quang ngin (dual 10'* s)

B Lan quang la svr phat quang c6 thai gian phat quang dai (10"* s tra len)

C Anh sang kich thich c6 buac song nho hon buac song ciia anh sang phat quang nen c6 the thupc vung anh sang nhin thay

D Buac song anh sang phat quang lan hom buac song anh sang kich thich nen

CO the thupc vCing hong ngo^i

Cau 35) Phat bieu nao sau day diing?

A Phan h^t cua mpt h^t sa cap c6 cung khoi lugmg va cung di^n tich

B H^t natrino khong mang di?n nen khong c6 phan h^t

C Photon chi ton t^i trong tr^ng thai chuyen dpng

D Chi CO ba lo^i tuang tac cua cac h^t sa cap la tuang tac hap dan, tirang tac difn tir va tuang tac m^nh

Cau 36) Chieu anh sang tir ho quang di?n vao tim kem trung hoa ve di?n dang

dirge d$t tren gia each di?n thi tam kem

A tich di^n am den mpt gia trj xac djnh nao do

B van trung hoa ve di?n

C tich di^n duang den mpt gia trj xac djnh nao do

D tich di^n am

Cau 37) Thvrc chat, tia phong x? P"

A dupe phong ra khi mpt natron trong h^t nhan phan ra thanh proton

B la electron trong h^t nhan bj kich thich phong ra

C la mpt phan nang lupng lien ket ciia h^t nhan chuyen hoa thanh electron

D la electron trong v6 nguyen tOr b| kich thich phong ra

Cau 38) Chpn phat bieu sai ve phan ung h^t nhan toa nSng lupng:

A Tong khoi lupng ciia cac h^t truac phan umg lan han tong khoi lupng ciia cac h^it sau phan ung

B Tong dp h\it khoi ciia cac h^t truac phan ung lan hon tong dp hyt khoi cua cac h^t sau phan ung

C Cac h^t nhan sau phan ung ben viJng hon cac h^t nhan truac phan ung

D Tong nSng lupng lien ket cua cac h^t nhan truac phan ung nho hom tong nSng lupng lien ket cua cac h^t sau phan ung

Cau 39) Cho phan ung h^t nhan

u 40 ) Ba

n ph

a bi ng h?t a thu dugc mgt h^

p = 1,0073

u; = 4,0015

u ;

mo

16,9947 u; u = 93

1 Me

V

Ph an un gn

Ca

u 41 ) Co

n \ic

dom (v^t n^n

g c

6 kho

i lugn

g m = 50

0 m/s

^ va

^

Gg

i T la

lyre cSn

g da

y kh

P

C T = P

D T

n m^c

h AB gom ty di?n c6 di?n dyng

C no

i tie

p va

U

0

7 1

C i =

1

=:rCos(a)t+

— )

B i = -

U

0

C O (_

COS((0t

)

co L- cos(cot —

)

6

D i =

o)C

V

1 eos(cot +

i da

u c

6 djnh Tre

n da

y dan

g

song dung v

ai n byng song, to

g tha

i gi

i

giua hai Ia

n m^c

h AB gom eugn day m5c noi tie

p v

ai di^

n t ra thuan D$

t vao

h

dau A , B mgt di?

n a

p xoa

y chie

u u = 10

0 \/

2 cos ( 1

OOTCI + ^ )

(V

) Di?

n

hi?u dyng giiia hai da

«0 ,6 C

ap

9(

Cau 46) MQt ty difn c6 difn dung C = 1 nF dirgrc tich d i | n den di^n ap c\ic dai Uo

roi noi vai cupn thuan cam c6 dp ty cam L = 10 mH de t^o thanh m^ch dao dpng Di?n tich tren ty bSng 0 vao thai diem nao ke tCr liic noi day?

, 71 „ Tt-lO"* ^ 37t.lO-^ ^ K I O - ' '

A s B s C s D s

5000 3 2 5

Cau 47) Trong thi nghi^m Y-ang ve giao thoa anh sang: Khoang each giGa hai khe

la a; khoang each tir hai khe den man la D Khi chieu vao hai khe anh sang c6

buac song -0,5 [im thi khoang van do dupe tren man la i | Khi chieu vao

hai khe anh sang c6 buac song =0,75 ^m, dong thai dua man l^i gan hai khe mpt do^n 50 cm thi khoang van do dupe tren man van la i i D c6 gia trj

A 1,5 m B 1 m C 2 m D 2,5 m

Cau 48) Phat bieu nao sau day sai?

A Kich thuac h^t nhan rat nho so vai kich thuac nguyen tir

B Hgt nhan dupe cau t^o tir cac nuclon

C H^t nhan nguyen tir mang d i | n tich duang

D Khoi lupng h^t nhan bat ki bing ^ khoi lupng nguyen tOr cua dong vj ^^C

Cau 49) Mpt thien ha khong chOra

A sao sieu mai B punxa C sao bien quang D quaza

Cau 50) Chpn y sal Chiim tia laze c6

A tinh djnh huang cao B tinh dan sac cao

C tinh ket hpp cao D buac song rat ngin

B Theo chirong trinh nang cao (tu* cau 51 den cau 60)

Cau 51) Chieu anh sang tim (A = 0,4 (xm) vao catot ciia mpt te bao quang di?n vai

cong suat chieu sang la 0,75 W thi xuat hi?n dong quang di?n Cuong dp dong quang di^n bao hoa do dupe la 3,2 mA Hif u suat lupng tir bSng

A 2,235% B 3% C 5% D 1,325%

Cau 52) Cuong dp dong quang di^n bao hoa

A tang khi giam buac song anh sang kich thich

B giam khi giam buac song cua anh sang kich thich

C tang khi tSng cuong dp cua chiim sang kich thich

D giam khi tSng cuong dp chiim sang kich thich

Cau 53) Mpt v^t ran dang quay deu quanh tryc thi chju tac dyng cua momen can

quay ch|m dan deu Trong thai gian t v^t quay dupe mpt goc 10 rad, dong thai dpng nang cua v^t giam 50 J Biet momen quan tinh cua v^t doi vai tryc quay la

I = 5 kgm^ gia toe goc cua v^t c6 dp Ian la

A 1 rad/s^ B 2 rad/s' C 3 rad/s^ D 4 rad/s"

Cau 54) Mpt v^t ran dang quay deu quanh tryc c6 djnh thi cac diem tren v^t

(khong thupc tryc quay)se

A chuyen dpng tren ciing quT d^o B c6 v^n toe dai bang nhau

C C O ciing hinh d^ng qui d^o D c6 gia toe huang tam bang nhau

211

Cau 55) D§

luon

giam,

Gia trj U

A U

c =

B

Ur = 2U,

a to

e go

c 4 rad/s^ Sa

u 1

0 s, mome

g 1

0 s, k

A 40

0 rad B 20

0 rad C 10

0 rad D 10

0 rad

Cau 57) Mg

t di^

n a

p u = Uocos(1007r

t + •^) dugr

i

A C-

=™

^F

C.C' = 10^

a X

C Ti

a gamm

a (y) D Ti

a a

Cau 59) Thie

t TrSng C Tra

i Dat D Th

6 tinh

Cau 60) Tron

thong tuan hoan?

A Lu

i 1

6 B Tie

n 1

6 C Tie

n 2

6

m/CWG DAN G IA

I

Cau 1) D Cau 2) C

Khoang thai gia

4

Cau 3) B

v$t C

O l

i d

p X = 2

cm = y

a d

i

2

theo chieu

am

T

12

212

DQ dan ciia 16 xo khi chi c6 v^t M la

A l = - ^ = 0 , l m

k Chpn goc the nSng tgi vj tri 16 xo dan 0,1 m

=> Nang lugmg cua h^ khi a vj tri nay la E = ^ k A p

Khi d$t v$t m len M , gpi A la dp dai cyrc d^i ciia hf ( M + m)

so vai goc the nSng

NSng luprng ciia h | luc nay la E' = ^ k ( A l + A)^ - ( M + m)gA

Do khong c6 ma sat nen nSng lupng ciia h? dupe bao toan

L\rc day evre d^ii tac dyng vao 16 xo F = k.(A -Al) = mg

L\rc hoi phye eye d^ii Fhp = k.A = 2mg = 2N

Do hai diem M , N each nhau 9 cm luon dao dpng dong pha nen ta eo 9 = k^

=> v$n toe truyen song v = = cm/s

k Theo de 70 cm/s < v < 80 cm/s => 5,625 < k < 6,428 => k = 6

V = 75 cm/s

Ciiu 9) C

213

Cau 10) B

M C

O bien

dp dao dpng c\rc d^i

V = X

f = 100 cm/s

Cau 11) B Cau

12) A

Cau 13) D

TirX = 2n

cVLC

;;

i; = 27t.c>/LC'

VaiC' = ^C=

>

> ^' =

y = 53,7

m

Cau 14) D Cau

15) B

Cau 16) A

Bien dp ciia suat di?n dpng

cam irng trong khung la

Eo =

NBSco = 345,5

8 V

Cau 17) B

Trong bieu thurc ch

i c

6 R

thay doi d

o do

Utmax khi R

= 0

Cau 18) C

D

o (

p ipi =

-—

< 0 nen

i nhan

h ho

n u

Cau 19) B Con

21) C

Cau 22) C

|n ap

hai da

u m

? ich

=>ZL-Z

c = r>/3^

=1

^^

50Q=

>r.^

Q

73 '

Cau 23} A

T Cr cong thuc

P

R =

R (R

+ r)2+(

ZL-Zc)'

Rmax khi

R o

R -

r^

+(

ZL-Zc)

au24)D

Dung khang ciia ty la Zc = = 80 Q

coC

Cam khang ciia CUQH day la Z L = coL = 30 Q

= 2 A => Di?n ap eye d^ii hai dau m^ch la Uo = IQZ

Ciiu 26) C

Do tia sang tring h^p vuong goc vai m$t ben cua

lang kinh nen no truyen thSng den I (hinh ve) Ap

dyng djnh lu^t khiic anh sang t^i 1

Tir eong thurc he - e U AK > Km = 49,1 pm

Ciiu 31) C Cau 32) D Cau 33) B Cau 34) D

Ciiu 35) C Cau 36) C Cau 37) A Cau 38) B

215

CS 3 9)

M5 X, o, 21 48

Cau

40) B

AE = (m

N +m„

nip-mo)c

T = mg(3cosa

- 2cosa

o ) = mg(ao

^ +

1 -

-^) ~

mg

= P

Cau 42) C Cau

43) C

Cau 44) D

— =

n ^

2f

21 Khoang thai gia

Dvra va

o gian do vecta =>

t =

n —(

n =1,3, 5,

)

4

Cau

47) A Khoang van tren man do dupe luc chieu anh sang c6 buac song^,

la

:

i, =

^(l) a

zM

(2 )

a

Tir(l)va (2) su

y r

a D = 1, 5 m

Cau 48) D Cau

49) D Cau

50) D

Cau 51) D

Cong suat chie

u san

g P = N

• he, = — i e — (vo N =)

e

A ,

216

Dong quang difn bao hoa Ibh = n.e (n s6 electron den anot trong Is cung la so electron thoat ra khoi catot trong mpt giay) n = -_Ibh

=> Hi?u suat lirgrng tu H = — = 1,325%

Sau khi momen lye thoi tac dyng v^t se quay deu voi toe dp goc 40 rad/s

=> Goc quay dupe la a = co.t = 40.10 = 400 rad

r>Zc=ion=>c' = —

n

217

ON LUYEN

Cau 1) Mp

i tha

i t = 0 lire ke

4 Hz C 4

rad/s

D 0,62

8 rad/s

Cau 2) Mp

o qu

a mp

i m

a sat Ti

cm C 4

cm D 1

, 6 cm

Cau 3) Mp

VQ

theo phuong

tiep tuyen, co

n li

e da

o

dpng qua Igi quan

i tha

i

diem l\re ho

C 0,33

4 J D 0,1J

Cau 5) Mp

C giam

D ban

g khong

Cau 6) Mp

eo khoi lupn

CO

dp cung

k = 100 N/m Ke

la

A —

s B -

s C —

s D —

218

Cau 7) Hai chat diem M , N chuyin dpng

tron deu tren hai dircmg tron dong tarn

ban kinh Ian iugt la 2 cm va 3 cm, vai

cung toe dp 60 vong/phut Liic t = 0;

M, N va O thing hang nhu hinh ve

Phuang trinh t6ng hgrp cua hinh chieu

hai chat diem xuong tryc Ox la

Cau 9) Thi nghi?m Y - ang giao thoa anh sang: nguon sang phat ra hai buc x? c6

buac song Ian lirpt la = 0,5 ^m va Xj = 0,75 |a.m Xet t^i M la van sang b^ic 6

cua van sang umg vai buac song Xi va t^i N la van sang b^c 6 ung vai buac

song X2 (M, N a cung phia doi vai tam O) Tren M N ta dem dupe

A 3 van sang B 5 van sang C 7 van sang D 9 van sang

Cau 10) Trong thi nghi?m ve giao thoa anh sang Y - ang: Hai khe Si va S2 c6

S1S2 = 1 mm va dupe chieu sang bai anh sang don sic c6 buac song 0,54.10'^

mm Khi giam khoang each tu hai khe S1S2 den man 1 m thi khoang van

A tang 0,54 mm B giam 0,54 mm

C tang 0,46 mm D khong doi

Cau 11) Nhi^t dp ciia mpt v^t phat sang cang cao, thi

A m'\kn quang pho thu dupe cang h?p

B vimg buc x9 c6 buac song dai cang sang

C vung mau sang nhat c6 buac song cang ngan

D mien quang pho cang rpng nhung dp sang cae vung nhu nhau

Cau 12) Tia tu ngo^i khong c6 tac dyng nao sau day?

A Lam da nguai ram nang, c6 mau banh m^t

B Khu trung nuac, th\rc pham va dyng cy y te

C Phat hi^n vet nut ben trong khoi kirn lo^i

D Kich thich s\ phat quang mpt so chat

Cau 13) Cong thoat electron ra khoi dong la 4,47 eV, h = 6,626 lO'^^Js, e = 1,6.10"

"C, c = 3.10'm/s De CO hi?n tupng quang di^n xay ra tren tkm dong, can chieu burc x^i CO buac song

C 0,447 0,2788 ^m D 0,2779 ^m

219

Cau 14) MQ

ki ba

n r

a T = 13

u tho

i gia

n t, kho

6 nga

y de

m

Cau 15) Kh

Cau 16) Ca

-Cau 17) Chg

Cau 18) Ch

o pha

n un

g h^i

t nhan:

^D+^

D-^jHe + n Pha

Cau 19) S\

t dg

Cau 20) Ti

Cau 21) Chg

n pha

t bie

u sai :

n do

220

22) Mpt chat phong c6 hing so phong la 5,68.10'^ s'V Chu ky ban ra cua

chat nay bang

A 4 s B 8,9 s C 124 s D 122 s

Cau 23) Chpn phat hiku dung:

A H^t nhan ben vCrng khi c6 khoi lucjmg trung binh va n^ng lugng lien ket lom

C Trong phong x^ c6 mpt natron da bien doi thanh mpt proton

D Trong s\ phan h^ch, h? so nhan natron la so natron can thiet de c6 phan ung day chuyen

Cau 24) Xet phan ung h^t nhan: j H e + ' 7 N -> {H + 'gO Bi6t h^t nhan Nita diimg

yen va phan umg thu nSng lirgmg 1,2103 MeV Cho m„ = 4,0015 u ; 1 u = 931,5

MeV/c^; c la v§n toe anh sang trong chan khong V^n toe toi thieu ciia h^t nhan

He de phan ung tren sinh ra c6 dp ion bang

A 0,02548c B 0,01557c C 0,03554c D 0,05562c

Cau 25) Cac tia phong x? deu

A CO ban chat song di^n tu

B khong bj Ifch trong di?n truang

C CO tinh ion hoa khong khi

D CO v | n toe bang v$n toe anh sang

Cau 26) Cho sa do thi nghifm nhu hinh v6:

bong den X; Cupn day L c6 loi thep ben

trong; Khoa K mac vao hai dau cugn day;

Hai dau A, B c6 difn ap xoay chieu Nh^n

djnh nao sau day sai ?

A K dong, den sang han khi K ma

B K ma, nit tu tu loi sat ra thi dp sang cua den tSng len

C K ma, nit tu tu 16i sat ra thi dp sang cua den giam

D L6i sat lam tang tinh cam khang ciia cupn day

Cfiu 27) Do^n m^ich di?n AB theo thu t\

gom 3 hpp X, Y, Z mac noi tiep Gpi

M la diem noi giCra X va Y; N la diem

noi giiia Y va Z M6i hpp chi chua

mpt trong 3 linh ki?n: di^n tra R ,

cupn day thuan cam L, ty di^n C Biet

di?n ap hi^u dyng giCra hai dau d o ^ m^ch A N bang difn ap hi?u dyng giua hai

dau do^ui m^ch MB va m^ch c6 tinh dung khang Nhu v^y, theo thu t\ X, Y, Z la

A R , C , L B L , R , C C C, R, L D R, L , C

Cau 28) Dpng ca di$n xoay chieu ba pha, c6 ba cupn day giong hft nhau mac hinh

sao M^ch di^n ba pha dung de ch^y dpng ca nay phai diing may day?

A 2 B.3 C 5 D 4

221

17/

Cau 29) Mp

u re moi ph

g d

{

dong di?n hi^u dyng qua moi cup

0A C 15A

D 2

0 A

Cau 30) P§

t R = 10

0 v

a c

o tha

y doi Kh

i di?n ap giua

hai ba

n

di?n l^ch pha ^ s

3 W C 300

W D 20

0 W

Cau 31) Ma

1 H vai mp

1 W

h v

a san

g ma

Cau 32) M^ic

C Tic

h di?n cho

ty hi?u di?n th

g d

p don

g di?n trong

m^ch khi nSn

D i =

R L,r

2

VL

Cau 33) Ch

ve, bie

t m^c

h M

CO tinh cam khang Do^

n ' j^^—TJMiT

m^ch nao sau day c6 h? s

o

cong suat nh

o nha

t ?

A MN B NP C

MP D NQ

Cau 34) Mp

H D$t giu

A i = 2V2sin(1007t

t + -)A B i

= 2sin(1007r

t + -) A

6 6

C i = 2V2sin(

1007tt )A D

i = 2sin(

1007it ) A

6 6

222

Cau 35) Mpt m^ch dao dpng LC ly tucmg, L = - H D$t

mgt di?n ap xoay chieu u = lOOcoslOOKt (V) vao hai

dau m^ch thi bien dp cuong dp dong di?n qua m^ch LC

ion nhat Di?n dung C c6 gia trj bang

Cau 36) Hinh ve nao sau day bieu dien moi lien h^ giira vec to cuong dp difn

truong E , vec to cam ixng tir B va phuong truyen song trong song di^nju?

Cau 37) D$t vao hai dau m^ch di?n RLC noi tiep mpt di^n ap xoay chieu c6 gia trj

hi?u dyng idiong d6i thi di?n ap h i | u dyng tren cac phan tir R, L va C deu bang nhau Khi tan so f cua dong di?n tSng thi

A cong suat tieu thy cua m^ch tang

B cuong dp dong di^n qua m^ich giam

C tong tra cua m^ch giam

D dif n ap hai dau dif n tra R tang

Cau 38) Mpt do^n m^ch xoay chieu RLC noi tiep c6 di^n tra thuan la 30 fJ Biet

difn ap hai dau ty C tre pha — so voi difn ap a hai dau do^n mgch, cupn day

6

chi CO cam khang la 70 Q Dung khang cua ty bang

Cau 39) Phuang trinh song dung tren mpt sgi day dan hoi c6 d^ng u = 2cos—sin 1 OOnt

(cm) (x do bang cm ; t do bang s) Toe dp truyen song tren day la

A 2 m/'s B 100 cm/s C 200 m/s D 1 m/s

Cau 40) Cac h^t so cap ben la

A proton B omega C mezon D hadron

223

II Pha

n neng :

Cau 41) Mp

0 g va day

A 0,0

2 rad B 0,0

1 ra

d C 0,0

3 rad D 0,0

4 rad

Cau 42) Thvr

cm Gp

i M la diem tren m$t cha

6in A

, B Ian lupt l

(di, di

ti'nh bSng cm) Co

i bien dp song khong

doi

So diem dao dpng vai bie

B 10

C 12

D 13

n than

h C

D

CO khoi lupn

g khon

g dan

g ke

Luc dau h$

dung yen, sa

u d

o ch

o

con lac 3 dao dpng Sa

u mp

t tha

i

gian ta thay con lac

A 1 dao dpng vai bie

n d

p Ia

n nhat

B 1, 2 va

C 4 dao dpng vai bie

n d

p Io

n nhat

D 2 dao dpng vai bien dp

Ian

nhAt

Cau 44) M

^ch

di?n gom

cupn

day mac no

i tie

p va

i ty, don

i = Iocos((ot+^) Nh^

Cau 45) M^c

la

A .=

I

6

B t = 0,5

T

T - t= C.

8 D.

.=

l

12

224

Cau 46) Thi nghi?m giao thoa anh sang boi Iche Y-ang: Tren man quan sat ta thay

6 van sang lien tiep each nhau 5,6 mm Xet hai diem M va N a hai ben van sang

trung tam va c6 khoang each den van sang trung tam Ian Ixxgt la 3,3 mm va 4,8

mm Gifta M va N c6 bao nhieu van toi ?

A 8 van toi B 6 van toi C 9 van toi D 7 van toi

Cau 47) Chpn y sai Tia tu ngo^i va tia Rorn ghen deu

A CO chung ban chat di$n tir B c6 tan so nho horn tan so tia gamma

C chua dugrc bf nh ung thu D gay ra nh&ng phan \jng quang hoa

Cau 48) H^t nhan ]'\Xc6 phong p"va ehu ki ban ra T Biet N A = 6,022.I0"

A 2,195.10" h?it

C 4,195.10" h^t

Cau 49) Thien Ha cua chiing ta

A con gQi la Ngan Ha

C con ggi la Thai Duong h^

B 3.13.10" h^t

D 2,195.10^^ h^t

B la thien ha clip

D chinh la thien ha Tien nu"

cugn day thuan cam L = — H Khi m&c nguon

71

di?n xoay chieu (100 V - 50 Hz) vao hai diem

A, C di^n thi so chi cua hai von ke nhu nhau va

bang

B Theo chirong trinh nang cao (tir 51 den 60 )

Cau 51) D^i lugrng nao sau day trong chuyen dpng quay cua v | t rin khong phai la

d^i lugng vecta ?

A Gia toe goe B V^n toe goc C V^in toe dai D T<?a dp goc Cau 52) Mpt thanh ddng chat khoi lugng 1 kg, dai

1 m quay quanh tryc nSm ngang (O la trung

diem cua thanh) V^t M luon gSn ch$t voi thanh

CO khoi lugmg 500 g Ban dau de thanh nSm

ngang Khi buong hf tht t6c dp goc ciia v^t M

khi thanh c6 phuong thSng dumg la

A.4,47rad/s B 4,9 rad/s C 7,74 rad/s D 2,36 rad/s Cau 53) Nh$n djnh nao sau day sai? Mpt v$t r4n quay nhanh dan quanh tryc c6

djnh, khi

A gia toe goc cung chieu voi v^n toe goe

B toe dp goe tang dan

C gia toe goc cung chieu voi v^n toe dai

D gia toe tiep tuyen cung chieu voi v^n toe dai

225

Cau 54) Mp

quan tinh 20 kgm^

va ban kinh 0,5

.20N C.62,8N D

1256N

Cau 55) Mp

t co

n \kc

16 xo treo theo phuang

thing dumg dao

cm D 3

cm

Cau 56) Tuan

n tir C ha

p din

D m^nh !

Cau 57) Do^

di?n va

cupn

da

y

khong thuan cam mac no

i tiep Gp

i M la diem noi gitr

C ra hai da

u do

^n m^ich A

B Dif

n tr

a r c6 gia trj

A 50

Q B

30

Q C lOO

Q D SO

Q

Cau 58) Kh

Js ;

e = 1,6.10'"

C ; m

e = 9,1.10'^' kg

6 }u

n D 0,48

2 pi

n

Cau 59) Ch

Biet 2.10"

* g ^

^A

u c

6

phong x?i 39,2

7 Ci, s

o Avogadr

o N

A =

6,022.1 O^^nguyen

tOr/mol I

A 2

4 phut B 4

8 phut C 1

2 phut D 6

0 phut

Cau 60) The

o Ha

p ban,

C ca

c thie

n h

a a xa

chiing

ta deu eo

nhi^t d

p ra

t cao

Hi rd NG D AN G IA

I

Cau

1 ) A

t = 0:

m co

^ x

= l=>o) = 20(rad/s)

226

Ta thay t^i M van sang b^c 6 cua X] triing vai van sang b^c 4 cua A.2 va van sang

b^c 9 ciia X] trung vai van sang b^c 6 cua X2 —* giOa M va N c6 cac van sang

khong trung nhau la van sang b^c 7,8 cua X\, van sang b$c 5 ciia X2 \'yy treii

NfN ta dem dugc 5 van sang

Cau 15 ) C ) D Cau 18

Cau 16 ) B

) A Cau 19

Cau 17 ) D ) A Cau 20

= 5,68.10" - ^ phong > g so Han ) D Cau 22

^

Cau 23 ) B

Cau 21 ) B

T = 122(s)

AE + W„=W„ +

Wo

•^mv^ >-AE :

-2AE

m -= 0,02548

c

Cau 26 ) C ) C ) D Cau 25 Cau 27

+ D

o so chi cu

2ZY ) >

U, = U2 x )^ y - Z - (Z + Z^ 2 R •

R^

= Zx (Zx -

2ZY ) >

108900J = 108,9kJ ) B Cau 33 ) C ) C Cau 32 Cau 34

IQ = — = 2 V2 A ,

cos(l OOTr

t

) =

2>^

sin(l

OOnt

XA) 6 co = t o 2 6 Ian nha g dp a cuom p cu 35) A Bien d u ca

Co nSng ban dau ciia con iSc la E = — mgla^o

G(?i Ooi la goc l?ch eye d^ii cua day treo sau khi con

lie th\rc hi?n dugrc nOra dao dao dpng

=> Co nang ciia con \ic t^'i vj tri nay la E' = ^ mgl ttQi

Ta CO dp bien thien nang lugng

A E = ^ m g i ( a o , - a o )

Ma dp bien thien nang lugng bSng cong cua l^rc can AE = Apc

=> mgl( O Q I - tto) = - Fc.S (vai S la quang duong v^t n^ng di dupe)

Cau 42) C

Nhung diem dao dpng vai bie

n d

p c\r

c d^

i A = 4 mm khi

cos[

(d2

- d,) +

- ] = ±

1 o -

(d2

- d|

) +

- = kTi

d, = 2 k- i (1)

Ta Igi c6

d2

+ d, = A

B =

12 c

m (2)

Tir(l)va (2) =

> d, = 5,75

- k

< k < 5,75

Do

CO

cung chieu dai ne

n li

e 3

=> con IJc 2

CO

cpng huong nen dao dpng vai bie

n d

p Ia

n nhk

Cau 44) D Ca

u 45 ) D

Cau 46) D

^i = 1,12 mm D

<k

<-—+

0,5->

3,44<

.-k<

3,78=

>k = {-3,-2, ,

-^

l-8,75g;

)-2T

= 2,1955.10^

^ h9t

-B

Cau 49) A Cau 50) A

Ve l

^i m^ch Nh$

Cau 51) D

Cau 52) B

Chpn goc th

e nSn

g t^

i O A

1 1

11

^ +M—)(o^ <=>(—m-rP = 0 g- -m IM)CO^ I + -( =mgl=>co

= 4,

9 rad/

Cau 53)

C

230

H M

Cau 60) A

ON LUYEN DAI HQC 4

LPhan chung cho tat ca thi sinh (gom 40 cau):

Cau 1) M p t v^t dao dpng dieu hoa v a i phuong trinh x = Acos( ^ ^ + ) T h a i

gian ke tir luc v§t c6 v^n toe bSng khong den luc v^t c6 toe dp bSng nura gia trj c\rc d^i cua no Ian t h u 3 la

I Cau 2) M p t chat diem dao dpng dieu hoa v a i tan so 5 Hz, bien dp 4 cm Gia toe

cvrc d^i cua chat diem bSng

231

i tha

i die

m t, l\r

y g = 1

0 m/s^

, nh

u v^y:

A

CO

> 1

0 rad/s B

co <

10 rad/s

C ©

> VT

O rad/s

D ©

<-Jl

O rad/

s

Cau 4) Mp

0 N/m, kh6

c t = 0, v$

t = — s dau tien

la

A 9,

3 cm B 7

cm C 7,

5 cm D 1

5 cm

Cau 5) Mp

0 g Da

t tre

n v§

t M mpt v$

t m = 9

0 g Tin

dao dpng

de m van nam yen tren v^t

M La

y g = 1

0 m/s^

A 6

cm B 8

cm

C

lOcm D 4

cm

Cau 6) Mp

t (N) Lu

0 g C 10

0 g D 20

g nan

g

va the nang cua v^t c

6 d

o th

j

nhu hinh

vg Layn

^ =10 V^

t

dao dpng vai bie

9 cm

C 15,

9 cm D 5

232

Cau 10) Cho tti^ich di^n gom hop X noi tiep vai mpt bong den. 0 hai dau hpp X c6

Idioa K Ta thay rang khi khoa K ma ho^c dong, den v i n sang binh thirong,

dieu nay chung to hpp X chua

A t\ di^n, difn tra B cupn day thuan cam, ty di?n

C cupn day, ty di?n D cupn day, difn tra

Cau 11) D$t vao hai dau do^n m^ich gom cupn day m5c noi tiep vai ty di^n mpt

difn ap xoay chilu B'lk di^n ap hifu dyng hai dau cupn day bSng di?n ap hifu

dyng hai dau m^ch M^ch nay c6

A cam khang bSng hai Ian dung khang B dung khang bSng hai Ian cam khang

C cam khang bSng dung khang D cam khang bang ba Ian dung khang

Cau 12) Cho m^ch difn gom bien tra (c6 gia trj tu 60^2 den vai tram Q) mac noi

1 2.10"^

tiep vai cupn day thuan cam L = — H va ty di^n c6 di?n dung C = — F

n n

Dat vao hai dau do^n m^ch di^n ap xoay chieu (220 V - 50 Hz) Khi cho bien

tra thay doi thi cong suat tieu thy tren R

A luon giam B luon tang C tang roi giam D khong thay doi

Cau 13) Mpt may bien the c6 so vong day a cupn so cap gkp 4 Ian so vong day a

cupn thu cap Mac vao hai dSu cupn thu cap vai mpt bong den c6 ghi 25 V De

den sang binh thuang, cm mic vao hai dau cupn so cap mpt di?n ap xoay chieu

CO gia trj hi^u dyng bang

A lOOV B 2 5 V C 50 V D 75 V

Cau 14) Trong do^in m^ich xoay chieu R L C noi tiep, ty difn c6 di?n dung thay doi

dupe Biet rang c6 hai gia trj C i va C2 cua ty d i | n c6 cong suat tieu thy trong

m^ich nhu nhau, va vai gia trj ciia di^n dung la Co thi cong suat tieu thy trong

m^ch eye d^i Moi lien h? giua C i , C2, Co la

Cau 15) D^t mpt di^n ap xoay chieu vao hai dau do^in m^ch A B theo thu ty ty di?n

va cupn day mac noi tiep Gpi M la diem noi giGa ty di^n va cupn day Biet UAM

= V 2 UMB va di?n ap giua hai dau AB nhanh pha 30° so vai di?n ap giira hai dau

do^n m^ch A M Di^n ap giua hai dau do^n m^ch M B nhanh pha so vai dong

di?n mpt goc la

A 45° B.90° C 60° D 75°

Cau 16) Doan m^ch di?n AB gom hai doan m^ch A M va M B mic noi tiep Khi d^t

mpt di^n ap xoay chieu hai dau A, B thi u ^ = 120V2cosl007rt (V) va

u ^ B =120V2cos(100nt + ^ ) ( V ) Bieu thuc dif n ap hai dau A B la

233

A = 240cos(1007rt +

0 mH Ha

a ha

i da

u do^

m^ch la

: U AB

= U \/2 coslOOTit Ba

n da

u d

p

l^ch pha giu

a U AB

B ciin

g ph

a i thi m^c

W C 5

0W

D 120

W

Cau 19) Tron

C dif

n tich, di^

n truang, don

g di?n va tir truang

va tuong tac

g iC

r a ca

c don

g di?n

Cau 20) Da

C ey

e ngSn D trun

g binh

Cau 21) Tron

g th

i nghi^

m Y

- ang: An

c kha

c nhau Bie

n trun

g ta

m

each nhau

2 mm S

D.9

Cau 22) Kh

mau do la

Cau 23) Tron

X

9 CO

mau

A do, van

g , cam, tim B cam

, do, lye, tim

C do, lam, tim, cham D lyc

, do, cam, cham

Cau 24) Ti

234

!au 25) Chieu cac tia X , hong ngo^i va t u ngo^ii den tam k i m l o ^ i c6 g i a i h^n

quang di?n thupc vung anh sang nhin thay N h u v§y:

A Ca ba tia khong gay ra hi^n tugiig quang di?n ngoai

B Tia X va tia tir ngo^i gay ra hi§n tugrng quang dl?n ngoai

C Tia X va tia hong ngo^i gay ra hi?n quang di^n ngoai

D Chi C O tia X gay ra hi^n tugng quang d i f n ngoai

C»u 26) Biet buac song umg v o i hai v^ch dau tien trong day Laiman la va A,L2 •

Buac song cua v^ch trong quang pho nhin thay ciia nguyen t u Hidro la

A j , ^ A i k 2 _ B ^ L i k 2

!au 27) Song sieu am va song anh sang deu

A C O v^n toe giam k h i di tir khong k h i vao nuac

B C O ban chat la song d i | n t u

C dugrc cau t^o tiJ cac photon

D C O h i | n tugng nhieu X 9 k h i g$p v^t can

Cau 28) Gia trj nao sau day bang ban kinh q u i d^o dung trong mau nguyen t u Bo?

A r = 2,12.10-'° m B r = 2,2.10-"'m

C.r = 6 , 3 1 0 ' ° m D r = 4,3.10-"'m

l u 29) Son dugc quet tren cac bien bao giao thong la son

A phat quang B phan quang

C lam bang cac chat huynh quang D hap thy anh sang

!au 30) Chat quang dan la chat

A chi dan di?n k h i c6 anh sang chieu vao

B phat sang khi c6 dong di^n di qua

C dan di?n tot khi c6 anh sang thich hgp chieu vao

D dugc dung de lam cac den L E D

Cau 31) Cho mc = 12,00 u, l u = 931 M e V / c ' H^t '^C c6 dpng nSng 3,575 M e V

thi dpng lugng cua no bang

A 43,15 MeV/c B 282,63 M e V / c

C 282,63 kgm/s D 282,63 M e V / c

]au 32) Poloni (^g4Po) la chat phong a va c6 chu ky ban ra la 138 ngay Hat

nhan con la h?t chi (•^g2Pb )• Tuoi cua mpt mau v^t t ^ i thai diem khoi lugng ciia

Po gap 4 Ian khoi lugng ciia Pb la

A 50 ngay B 27 ngay C 69 ngay D 45,2 ngay

Cau 33) Phong

A la mpt phan ung phan h^ich h^t nhan nen toa nang lugng

B C O h^t nhan con sinh ra luon a t r ^ i g thai kich thich

C chi xay ra k h i h^it nhan a tr^ng thai ki'ch thich

D la qua trinh phan ra cua mgt h^t nhan khong ben vCmg thanh cac h^t nhan khac

Cau 34) Ca

, Y

la mpt tron

g b

a pha

n t

u R, C va cupn day (c6 di?n tra r) D$

t va

o h

i

dau do^n m^ch mpt di?

n a

p u = uV2sinl007r

, Y

do dugrc Ia

X va

n da

y v

a t

y C

C t

y C va di^n tra

R D di

f n tra

R v

a cup

n day

(mm)

k (

k l

a s

o nguyen)

Cau 37) Mp

i

song

CO CO

d^ng nhu hinh

i O Son

B B B

den

A

C M den

N D N

den

M

Cau 38) Thy

i X

la buac song D

Cau 40) Tron

g quan

g ph

o hidro: Kh

i electro

n a

muc nang lupng kich thich

thu

tu

tra ve cac mu

c nan

g lupn

g be

n trong, c

?

A 4

B

3 C.2 D

5

236

H, Phan rieng:

A Tbeo chirorng trinh chuan (tir cau 41 den cau 50)

Cau 41) Mpt con lac 16 xo treo theo phuorng thing dung dao dpn^ dieu hoa t^i nai

CO gia toe trpng truong g = 10 m/s^ Khi v§t a vj tri cao nhat thi Ivrc dan hoi

bing lye keo ve, gia toe v$t luc eo dp Ion bang

Cau 42) Mpt eon lac don dao dpng dieu hoa vai phuomg trinh: s = Soeos(27it+^)

T?ii thai diem t = 0, t i so giua dpng nang va ea nang bang

A 0,5 B.0,25 C.0,75 D 0,66

Cau 43) Thi nghi^m hifn tupng giao thoa tren m$t nuac tCr hai nguon A , B c6 eiing

tin so, eung bien dp, cung pha Gpi C la d i l m nam tren duong trung tr\rc cua

A B sao eho A B C la tam giae deu Biet buae song bang dp dai A B , nhu Y§y tren

duong cao CH cua tam giae c6 bao nhieu diem dao dpng cung pha vai nguon?

Cau 44) D$t mpt di^n ap xoay chieu vao hai dau mpt dif n tra R thi dong d i | n qua

di?n tra c6 bieu thue IR =Ioeoso)t Khi d$t dif n ap noi tren vao hai ban ty di§n eo

dien dung C thi dong di?n qua t\ c6 bieu thiic

A \Q = Ra)CIoCos(cot + ^ ) 8 1 ^ = RcoCI(,cos(cot - ^ )

C. ic = RcoCIj, sin (cot + ^ ) D i ^ = RCOCIQ coswt

Cau 45) Mpt song di?n tCr c6 tan so 3.10* Hz truySn trong nuac vai v^n toe 2,7.10*

m/s Buac song ciia song di^n tCr tren khi truyen trong nuac la

Cau 46) Cho m^ieh xoay chieu RLC noi tiep: Difn ap hi?u dyng hai dau m^ch la

U = 120V va CO tan so f xac djnh; Biet CR^ = 16L, d6ng thai m^eh c6 epng

huomg Di$n ap hai dau ty C bSng

A 60 V B 50 V C 3 0 V D 9 0 V

Cau 47) Trong thi nghi?m ve giao thoa anh sang Y - ang: Gpi i la khoang van,

khoang each n van lien tiep bang

A n B n C ( n 1 ) D (n + 1 )

-2 -2 -2 -2

Cau 48) Tia Laze ho^t dpng dpng dvra vao

A svr phat x^i cam ung B s\t buc di?n tir

C hi$n tupng quang di^n B hi$n tupng cam ung di?n tir

Cau 49) Nang lupng lupng lien ket rieng ciia h^t nhan doteri ( ^ D ) la 1,1

MeV/nuclon va ciia h^t nhan Heli ( 2 H e ) ' l a 7 MeV/nuelon Nang lupng toa ra

khi hai h^t nhan \ tong hpp thanh h^it nhan 2 He bang

A.30,2MeV B 23,6 MeV C 19,2MeV D 25,6 MeV

Cau 50) Tuang tac giiia cac h^t trong phan trong phan ra P la tuang tac

A hap dan B di?n tir C yeu D m^inh

237

Cau 51) Tron

g s\

lien h? giu

1 ch

u ki

Cau 52) Co

n

I Sc dao dpng vai ch

T2 = — T

D.

Cau 53) Chie

di?ii,

electron thoat r

dp

I61

bang 1,18V Bua

c son

g X' hkng

A 0,50

4 ^

m B 0,5

4 ^i

m C 0,40

5 ^

m D 0,4

5 ^

m

Cau 54) Ch

2 C 0,75

8 D 0,08

2

Cau 55) Tron

natrino C

proton D

natron

Cau 56) Mp

C 4

Wb D.4.10-^Wb

Cau 57) Kh

i mp

t v^

t rkn

quay ch^m dan deu quanh mpt try

Cau 58) Mp

t die

m M tren v^t ra

0

+1 +1^

rad Xa

c djn

h , biet lu

= 4rad

A 4 rad B 2

rad C

6 rad D 3

rad

238

Cau 59) M p t v^t r4n dang quay quanh mgt tryc c6 djnh, momen quan tinh 0,5 kgm^ Toe dp v§t thay doi deu tir 0 den 300 vong/phut trong khoang 3,14 giay

Dp bien thien momen dpng lupng trong khoang t h a i gian tren la

B 10 k g m W C 100 k g m V s ' D 31,4 k g m V

A 5 kgmW

Cau 60) Cho h? n h u hinh ve (vgt m luon gin ch$t

vai h?) K h o i try d$c quay quanh mpt tryc nkm

ngang c6 k h o i l u g n g M = 2 m , ban kinh R = 5

cm, g =10 m/s^ Luc dau gi& h | dung yen, toe

dp goc cua h? k h i m den v j t r i c6 a = 60^ la

Do luc t = 0 v ^ t d i qua v j t r i can bSng nen

quang duang tuang ung v^t d i dupe la s A + y = 7,5 c m

Cau 5) C

Khi hai v$t d i len, chiing luon tiep xiic nhau va

m khong the r a i khoi M

Trong qua trinh d i xuong, dieu k i ^ n de m

khong r a i khoi M la a < g => co^ < g

Bien dp dao dpng cuong buc eye d^ii k h i tan so rieng coo cua 16 x o bang tan so

Cau 7) D

T u d o t h i t a c o : - = 0,125

8 NSng lupmg: W = - ^ m { o ^ A = 0,01

T = Is - > CO = 27t rad/s

A = 5cm

239