20 Piv txwv ntawm cov lus nug txog hluav taws xob zoo li qub
Lub zog hluav taws xob
1. Qhov chaw A nyob hauv ib lub teb hluav taws xob . Lub zog hluav taws xob ntawm qhov chaw A yog 0,5 NC -1 . Yog tias ib yam khoom uas muaj lub zog ntawm 0,25 C raug muab tso rau ntawm qhov chaw A, ces lub zog Coulomb ntawm...
A. 0,125 N
B. 0,25 N
C. 0,35 N
D. 0,40 N
Sab Hnub Tuaj 0,70 N
Kev Sib Tham
Nws paub tias:
Lub zog hluav taws xob ntawm qhov chaw A = 0,5 NC -1
Lub zog hluav taws xob ntawm qhov chaw A = 0,25 C
Lus Nug: Lub zog Coulomb ua rau ib yam khoom uas raug hluav taws xob
Lus teb:
Cov mis uas qhia txog kev sib raug zoo ntawm lub zog hluav taws xob (F), lub zog hluav taws xob (E) thiab lub zog hluav taws xob (q) yog:
F = qE
F = (0,25 C)(0,5 NC -1 )
F = 0,125 N
Cov lus teb yog lawm yog A.
2. Ob lub zog ntawm 5 C thiab 4 C nyob sib nrug 3 m. Yog tias k = 9 × 10 9 Nm 2 C –2 , ces qhov loj ntawm lub zog Coulomb uas ob lub zog ntawd ntsib yog…
A. 2 × 10 9 N
B. 60 × 10 9 N
C. 2 × 10 10 N
D. 6 × 10 10 N
E. 20 × 10 10 N
Kev Sib Tham
Nws paub tias:
Them 1 (q 1 ) = 5 C
Them 2 (q 2 ) = 4 C
Qhov nrug ntawm cov khoom thauj 1 thiab 2 (r) = 3 meters.
Coulomb tas li (k) = 9 × 10 9 Nm 2 C –2
Lo lus nug: Qhov loj ntawm Coulomb lub zog (F)
Lus teb:
Cov lus teb yog C.
3. Cov nqi hluav taws xob +q 1 = 10 μC; +q 2 = 20 μC; thiab q 3 raug sib cais raws li pom hauv daim duab hauv qab no. Yog li ntawd lub zog Coulomb ua rau lub nqi q 2 = xoom; ces lub nqi q 3 yog…
A. +2,5 μC
B. –2,5 μC
C. +25 μC
D. –25 μC
E. +4 μC
Kev Sib Tham
Nws paub tias:
Them 1 (q 1 ) = 10 μC = 10 x 10 -6 C
Them 2 (q 2 ) = 20 μC = 20 x 10 -6 C
Lo lus nug: Tus nqi q 3 yog dab tsi kom lub zog Coulomb ua rau tus nqi q 2 sib npaug rau xoom (F 2 = 0).
Lus teb:
Muaj ob lub zog ua haujlwm rau + q2.
Lub zog thawj zaug yog lub zog repulsive ntawm tus nqi +q 1 thiab tus nqi +q 2 , uas yog F 12 , uas yog taw qhia rau sab xis.
Rau qhov tshwm sim ntawm lub zog hluav taws xob uas ua rau q 2 yog xoom, q 3 yuav tsum muaj tus nqi tsis zoo . Yog li ntawd, lub zog thib ob yog lub zog nyiam ntawm cov nqi +q 2 thiab -q 3 , uas yog F 23, uas yog taw qhia rau sab laug. Ob lub zog no uas ua rau q 2 muaj tib qhov loj tab sis cov lus qhia sib txawv.
Lub zog tshwm sim ntawm +q2 yog sib npaug rau xoom.
Cov lus teb yog B.
4. Cov ntsiab lus A thiab B muaj lub zog hluav taws xob ntawm −10 μC thiab +40 μC feem. Thaum xub thawj, ob lub zog raug muab tso rau 0,5 meters sib nrug kom lub zog Coulomb F Newton tshwm sim. Yog tias qhov deb ntawm A thiab B raug hloov mus rau 1,5 meters, ces lub zog Coulomb uas tshwm sim yog...
A. 1 / 9 F
B. 1 / 3 F
C. 3 / 2 F
D. 3 F
Sab Hnub Tuaj 9 F
Kev Sib Tham
Piv cov lus sib tham ntawm lo lus nug lej 9.
Qhov kev ncua deb ntawm A thiab B raug hloov mus rau 1,5 meters lossis 3 npaug ntawm qhov kev ncua deb qub.
Lub zog yog inversely proportional rau lub square ntawm qhov deb:
Lub zog Coulomb uas tshwm sim yog 1/9 F.
Cov lus teb yog lawm yog A.
5. Ib lub kaw lus uas muaj 3 lub nqi dawb uas muaj qhov loj sib npaug raug muab tso rau kom nws sib npaug raws li pom hauv daim duab. Yog tias Q 3 raug txav mus ze rau Q 2 1/3 x , ces qhov piv ntawm qhov loj ntawm lub zog Coulomb F 2 : F 1 dhau los ua….
A. 1: 3
B. 2: 3
C. 3: 4
D. 9: 1
E. 9: 4
Kev Sib Tham
Nws yog paub tias :
Qhov nrug ntawm q 1 thiab q 2 = x
Qhov nrug ntawm q 2 thiab q 3 = 2/3 x
Nug : F 2 : F 1 = .... ?
Lus teb :
Cov qauv ntawm Coulomb txoj cai lij choj:
Kev piav qhia: k = tas li, q 1 = them 1, q 2 = them 2, r = nrug ntawm them 1 thiab them 2
Kev sib piv ntawm qhov loj ntawm lub zog Coulomb
q 1 , q 2 thiab q 3 sib npaug zos yog li lawv raug tshem tawm ntawm qhov sib npaug. k thiab x 2 kuj yog tib qhov loj me thiab nyob rau sab laug thiab sab xis yog li lawv raug tshem tawm ntawm qhov sib npaug.
Cov lus teb yog yog E.
6. Saib daim duab hauv qab no. Peb lub zog hluav taws xob q 1 , q, thiab q 2 nyob hauv ib kab. Yog tias q = 5,0 μC thiab d = 30 cm, ces qhov loj thiab kev coj ntawm lub zog hluav taws xob ua rau lub zog q yog… (k = 9 x 10 9 N m 2 C -2 )
A. 7,5 N mus rau q1
B. 7,5 N mus rau q 2
C. 15 N mus rau q 1
D. 22,5 N mus rau q 1
E. 22,5 N mus rau q 2
Kev Sib Tham
Nws paub tias:
Them 1 (q 1 ) = 30 μC = 30 x 10 -6 C
Them 2 (q 2 ) = 60 μC = 60 x 10 -6 C
Them 3 (q) = 5 μC = 5 x 10 -6 C
Qhov nrug ntawm q 1 thiab q = d
Qhov nrug ntawm q 2 thiab q = 2d
d = 30 cm = 0,3 meters
d 2 = (0,3) 2 = 0,09
Coulomb tus nqi tas mus li (k) = 9 x 10 9 N m 2 C -2
Lus Nug: Qhov loj thiab kev coj ntawm lub zog hluav taws xob ua rau lub zog hluav taws xob
Lus teb:
Muaj ob lub zog ua rau q, uas yog F 1 raug coj mus rau sab xis (q thiab q 1 raug them zoo kom F 1 nyob deb ntawm q thiab q 1 ) thiab F 2 raug coj mus rau sab laug (q thiab q 2 raug them zoo kom F 2 nyob deb ntawm q thiab q 2 ). Ua ntej xam F 1 thiab F 2.
Lub zog tshwm sim:
Σ F = 15 – 7,5 = 7,5
Lub zog tshwm sim yog 7,5 Newtons. Nws qhov kev taw qhia yog tib yam li F 1 , uas yog mus rau sab xis ntawm q 2.
Cov lus teb yog B.
Lub zog hluav taws xob
7. Ib qho chaw them q nyob ntawm qhov chaw P hauv ib lub teb hluav taws xob uas tsim los ntawm ib qho chaw them (+) kom nws muaj lub zog ntawm 0,05 N hauv kev coj mus rau qhov chaw them. Yog tias lub zog ntawm lub teb ntawm qhov chaw P yog 2 x 10 –2 NC –1 , ces qhov loj thiab hom ntawm cov nqi uas tsim lub teb yog…
A. 5,0 C, zoo
B. 5,0 C, tsis zoo
C. 3,0 C, zoo
D. 2,5 C, tsis zoo
E. 2,5 C, zoo
Kev Sib Tham
Nws paub tias:
Lub zog hluav taws xob (F) = 0,05 N
Lub zog hluav taws xob (E) = 2 x 10 –2 NC –1 = 0,02 NC –1
Nug: Qhov loj thiab hom nqi uas tsim lub teb
Lus teb:
Lub zog hluav taws xob raug suav los ntawm kev siv cov qauv uas qhia txog kev sib raug zoo ntawm lub zog hluav taws xob (F), lub teb hluav taws xob (E) thiab lub zog hluav taws xob (q):
F = qE
q = F / E = 0,05 N / 0,02 NC –1 = 2,5 Coulombs
Tus nqi q muaj lub zog hluav taws xob nyob rau hauv qhov kev taw qhia mus rau tus nqi (+) uas tsim ib lub teb hluav taws xob, yog li tus nqi q muaj lub cim tsis zoo.
Cov lus teb yog D.
8. Qhov nrug ntawm ob lub nqi A thiab B yog 4 m. Qhov chaw C yog nyob nruab nrab ntawm ob lub nqi, 1 m ntawm A. Yog tias Q A = –300 μC, Q B = 600 μC. 1/4 π ε 0 = 9 × 10 9 N m 2 C –2 , ces lub zog hluav taws xob ntawm qhov chaw C vim yog kev cuam tshuam ntawm ob lub nqi yog…
A. 9 × 10 5 NC –1
B. 18 × 10 5 NC –1
C. 33 × 10 5 NC –1
D. 45 × 10 5 NC –1
E. 54 × 10 5 NC –1
Kev Sib Tham
Nws paub tias:
Qhov nrug ntawm cov khoom thauj A thiab B (r AB ) = 4 meters
Qhov nrug ntawm qhov chaw C thiab lub zog them A (r AC ) = 1 meter
Qhov nrug ntawm qhov C thiab lub zog them B (r BC ) = 3 meters
Tus nqi A (q A ) = –300 μC = -300 x 10 -6 C = -3 x 10 -4 Coulomb
Tus nqi B (qB ) = 600 μC = 600 x 10 -6 C = 6 x 10 -4 Coulomb
Qhov ruaj khov (k) = 9 × 10 9 N m 2 C –2
Lus Nug: Lub zog hluav taws xob ntawm qhov chaw C
Lus teb:
Lub zog hluav taws xob uas tsim los ntawm tus nqi A ntawm qhov chaw C:
Tus nqi A yog qhov tsis zoo yog li qhov kev taw qhia ntawm lub zog hluav taws xob yog mus rau tus nqi A thiab deb ntawm tus nqi B (mus rau sab laug).
Lub zog hluav taws xob uas tsim los ntawm tus nqi B ntawm qhov chaw C:
Tus nqi B yog qhov zoo yog li qhov kev taw qhia ntawm lub zog hluav taws xob nyob deb ntawm tus nqi B thiab mus rau tus nqi A (mus rau sab laug).
Lub zog hluav taws xob tshwm sim ntawm qhov chaw A:
E A thiab E B nyob rau tib qho kev taw qhia yog li lawv raug ntxiv ua ke.
E = E A + E B
E = (27 x 105 ) + (6 x 105 )
E = 33 x 10 5 N/C
Lub zog hluav taws xob ntawm lub zog A mus rau sab laug thiab sab xis (mus rau sab laug).
Cov lus teb yog C.
9. Ib lub hmoov av uas hnyav 1 milligram tuaj yeem ntab saum huab cua vim yog lub zog hluav taws xob uas tuav cov hmoov av. Yog tias lub zog ntawm cov hmoov av yog 0,5 μC thiab qhov kev nrawm vim yog lub ntiajteb txawj nqus yog 10 m/s2 , txiav txim siab qhov loj ntawm lub zog hluav taws xob uas tuaj yeem tuav cov hmoov av.
A. 5 N/C
B. 10 N/C
C. 20 N/C
D. 25 N/C
E. 40 N/C
Kev Sib Tham
Nws paub tias:
Qhov hnyav ntawm hmoov av (m) = 1 milligram = 1 x 10 -6 kg
Cov hmoov av (q) = 0,5 μC = 0,5 x 10 -6 C
Kev nrawm vim lub ntiajteb txawj nqus (g) = 10 m/s 2
Lo lus nug: Lub zog ntawm lub zog hluav taws xob uas tuav cov hmoov av
Lus teb:
Qhov hnyav mis:
w = mg
Kev piav qhia: w = qhov hnyav ntawm hmoov av, m = pawg ntawm hmoov av, g = kev nrawm vim yog lub ntiajteb txawj nqus
Lub zog gravitational uas ua rau plua plav lossis qhov hnyav ntawm plua plav yog suav los ntawm kev siv cov mis hnyav:
w = mg = (1 x 10 -6 kg)(10 m/s 2 ) = 10 x 10 -6 kg m/s 2 = 10 x 10 -6 Newtons
Lub zog fais fab teb mis:
E = F/q
Kev piav qhia: E = lub zog hluav taws xob, F = lub zog hluav taws xob, q = lub zog hluav taws xob
Cov hmoov av ntab saum huab cua, yog li lub zog uas ua rau cov hmoov av yuav tsum yog xoom. Lub ntiajteb txawj nqus ntawm cov hmoov av raug coj mus rau hauv qab, yog li lub zog hluav taws xob yuav tsum raug coj mus rau saum toj, thiab qhov loj ntawm lub ntiajteb txawj nqus ntawm cov hmoov av yuav tsum sib npaug rau qhov loj ntawm lub zog hluav taws xob, yog li lub zog uas ua rau cov hmoov av yog xoom. Yog li, F hauv cov mis ntawm lub zog hluav taws xob tuaj yeem hloov los ntawm w hauv cov mis hnyav.
E = F/q = w/q
E = (10 x 10 -6 N) / (0,5 x 10 -6 C)
E = 10 N / 0,5 C
E = 20 N/C
Cov lus teb yog C.
10. Ob lub nqi, q 1 = 32 μC thiab q 2 = -214 μC, raug sib cais los ntawm qhov deb x ntawm ib leeg raws li pom hauv daim duab saum toj no. Yog tias ntawm qhov chaw p, uas yog 10 cm ntawm q 2, lub zog hluav taws xob tshwm sim yog xoom. Ces qhov loj ntawm x yog….
A. 20 cm
B. 30 cm
C. 40 cm
D. 50 cm
E. 60 cm
Kev Sib Tham
Nws paub tias:
Them 1 (Q 1 ) = 32 μC
Them 2 (Q 2 ) = -214 μC
Qhov nrug ntawm qhov p ntawm q 1 = x + 10 cm
Qhov nrug ntawm qhov p ntawm q 2 = 10 cm
Nug: x
Lus teb:
E 1 yog lub teb hluav taws xob uas tsim los ntawm tus nqi Q 1. Qhov kev taw qhia ntawm lub teb hluav taws xob yog deb ntawm Q 1 vim Q 1 yog tus nqi zoo. E 2 yog lub teb hluav taws xob uas tsim los ntawm tus nqi Q 2. Qhov kev taw qhia ntawm lub teb hluav taws xob yog mus rau Q 2 vim Q 2 yog tus nqi tsis zoo.
Ntawm qhov chaw p uas yog 10 cm ntawm Q2 , lub zog hluav taws xob tshwm sim yog xoom.
Siv cov qauv ABC:
11. Ib qho chaw uas muaj tus nqi q nyob ntawm qhov chaw P hauv lub teb hluav taws xob uas tsim los ntawm tus nqi (+), yog li nws muaj lub zog ntawm 0,05 N. Yog tias qhov loj ntawm tus nqi yog +5 × l0 –6 Coulomb, ces qhov loj ntawm lub teb hluav taws xob ntawm qhov chaw P yog…
A. 2,5 × 10 3 NC –1
B. 3.0 × 10 3 NC –1
C. 4,5 × l0 3 NC –1
D. 8,0 × 10 3 NC –1
E. 10 4 NC –1
Kev Sib Tham
Nws paub tias:
Lub zog hluav taws xob (F) = 0,05 Newton
Lub zog hluav taws xob (Q) = +5 × l0 –6 Coulomb = 0,000005
Lus Nug: Qhov loj ntawm lub zog hluav taws xob ntawm qhov chaw P yog dab tsi?
Lus teb:
Cov mis uas qhia txog kev sib raug zoo ntawm lub zog hluav taws xob, lub zog hluav taws xob thiab lub zog hluav taws xob:
E = F / Q
E = 0,05 Newtons / 0,000005 Coulombs
E = 5 Newtons / 0,0005 Coulombs
E = 10.000 Newton/Coulomb
E = 10 4 N/C
E = 10 4 NC -1
Cov lus teb yog yog E.
12. Peb lub nqi tau teeb tsa raws li qhia hauv daim duab hauv qab no. Lub zog Coulomb uas lub nqi B raug yog .... (k = 9 x 10 9 Nm 2 C −2 , 1 μC = 10 −6 C)
A. 09 x 101 N txog C them
B. 09 x 101 N kom them A
C. 18 x 101 N txog C them
D. 18 x 101 N kom them A
E. 36 x 101 N txog C them
Kev Sib Tham
Nws yog paub :
qA = 10 µC = 10 x 10-6 C = 10-5 Coulomb
qB = 10 µC = 10 x 10-6 = 10-5 Coulomb
qC = 20 µC = 20 x 10-6 Luas = 2 x 10-5 Coulomb
rAB = 0,1 meters = 10-1 'meter'
rBC = 0,1 meters = 10-1 'meter'
k = 9 x 109 Nm2C-2
Nug Lub zog Coulomb raug los ntawm tus nqi B
Jawb :
Muaj ob lub zog Coulomb lossis lub zog hluav taws xob uas ua rau lub zog B, uas yog lub zog Coulomb ntawm cov nqi A thiab B (F AB ) thiab lub zog Coulomb ntawm cov nqi B thiab C (F BC ). Lub zog Coulomb uas lub zog B ntsib yog qhov tshwm sim ntawm F AB thiab F BC.
Lub zog Coulomb ntawm cov nqi A thiab B:
Tus nqi A muaj lub cim zoo thiab tus nqi B muaj lub cim zoo yog li FAB mus rau qhov them C.
Lub zog Coulomb ntawm cov nqi B thiab C:
Tus nqi B yog qhov zoo thiab tus nqi C yog qhov zoo yog li ntawd FBC mus rau qhov them nqi A.
Lub zog Coulomb uas raug los ntawm tus nqi B:
FB =FBC - FAB = 180 – 90 = 90 N
Qhov loj ntawm lub zog Coulomb uas raug los ntawm tus nqi B (F)B) yog 90 Newtons. Qhov kev taw qhia ntawm FB zoo ib yam li kev taw qhia FBC uas yog rau tus nqi A.
Cov lus teb yog B.
13. Qhov loj thiab kev coj ntawm lub zog Coulomb ntawm tus nqi B yog... (k = 9 x 10 9 Nm 2 C −2 , 1 μC = 10 −6 C)
A. 2,5 k Q2 r-2 mus rau sab laug
B. 2,5 k Q2 r-2 mus rau sab xis
C. 2 k Q2 r-2 mus rau sab laug
D. 2 k Q2 r-2 mus rau sab xis
E. 1 k Q2 r-2 mus rau sab laug
Kev Sib Tham
Nws yog paub :
Them A (qA) = +Q
Tus nqi B (qB) = -2Q
Them C (qC) = -Q
Qhov nrug ntawm cov nqi A thiab B (r)AB) = r
Qhov nrug ntawm cov nqi B thiab C (r)BC) = 2r
k = 9 x 109 Nm2C-2
Nug : qhov loj thiab kev coj ntawm lub zog Coulomb ntawm tus nqi B
Jawb :
Lub zog Coulomb ntawm tus nqi A thiab tus nqi B:
Tus nqi A yog qhov zoo thiab tus nqi B yog qhov tsis zoo yog li qhov kev taw qhia yog FAB mus rau tus nqi A
Lub zog Coulomb ntawm tus nqi B thiab tus nqi C:
Tus nqi B yog qhov tsis zoo thiab tus nqi C yog qhov tsis zoo yog li qhov kev taw qhia ntawm F yogBC mus rau tus nqi A
Lub zog ua rau lub zog B:
F = FAB +FBC = 2 k Q2/r2 + 0,5 k Q2/r2 = 2,5 k Q2/r2 = 2,5 k Q2 r-2
Qhov kev taw qhia ntawm lub zog Coulomb yog mus rau qhov them A lossis mus rau sab laug.
Cov lus teb yog lawm yog A.
Lub zog hluav taws xob
14. Saib daim duab hauv qab no ntawm ob lub ntsiab lus them! Qhov chaw P nyob qhov twg kom lub zog hluav taws xob ntawm qhov chaw P sib npaug rau xoom? (k = 9 x 109 Nm2C-2, 1 μC = 10-6 C)
A. nyob nruab nrab ntawm Q1 thiab Q2
B. 6 cm rau sab xis ntawm Q2
C. 6 cm rau sab laug ntawm Q1
D. 2 cm rau sab xis ntawm Q2
E. 2 cm rau sab laug ntawm Q1
Kev Sib Tham
Yuav xam lub zog hluav taws xob ntawm qhov chaw P, xav tias muaj qhov them nqi kuaj zoo ntawm qhov chaw P. Q.1 zoo thiab Q2 tsis zoo, yog li ntawd qhov P yuav tsum nyob rau sab xis ntawm Q2 los yog sab laug ntawm Q1. Yog tias qhov chaw P nyob rau sab laug ntawm Q1lub teb hluav taws xob uas tsim los ntawm qhov Q1 ntawm qhov chaw P qhov kev taw qhia yog sab laug (deb ntawm Q1) thiab lub zog hluav taws xob tsim Q2 ntawm qhov chaw P qhov kev taw qhia yog mus rau sab xis (mus rau Q)1). Vim tias qhov kev taw qhia ntawm lub zog hluav taws xob nyob rau sab nraud, ob qho tib si tshem tawm ib leeg kom lub zog hluav taws xob ntawm qhov chaw P yog xoom.
Nws yog paub :
Q1 = +9 μC = +9 x 10-6 C
Q2 = -4 μC = -4 x 10-6 C
k = 9 x 109 Nm2C-2
Qhov nrug ntawm tus nqi 1 thiab tus nqi 2 = 3 cm
Qhov nrug ntawm Q1 thiab qhov chaw P (r1P) = ib
Qhov nrug ntawm Q2 thiab qhov chaw P (r2P) = 3 + ib
Nug Qhov chaw P nyob qhov twg kom lub zog hluav taws xob ntawm qhov chaw P sib npaug rau xoom?
Jawb :
Point P yog sab laug ntawm Q1.
Lub zog hluav taws xob uas tsim los ntawm Q1 ntawm qhov chaw P :
Tus nqi kuaj zoo thiab Q1 zoo yog li ntawd qhov kev taw qhia ntawm lub teb hluav taws xob yog mus rau sab laug.
Lub zog hluav taws xob uas tsim los ntawm Q2 ntawm qhov chaw P :
Tus nqi kuaj zoo thiab Q2 negative yog li ntawd qhov kev taw qhia ntawm lub teb hluav taws xob yog mus rau sab xis.
Lub zog hluav taws xob tshwm sim ntawm qhov chaw A :
E1 thiab E2 kev taw qhia txawv.
E1 - E2 = 0
E1 = E2
Siv cov qauv ABC los txiav txim siab tus nqi ntawm a.
a = -1,25, b = -13,5, c = -20,25
Nws tsis tuaj yeem yog qhov tsis zoo.
Qhov nrug ntawm Q2 thiab qhov chaw P (r2P) = 3 + a = 3 – 1,8 = 1,2 cm.
Point P nyob ntawm qhov deb ntawm 1,2 cm rau sab xis ntawm Q.2.
15. Saib daim duab hauv qab no! Them q3 muab tso rau ntawm qhov deb ntawm 5 cm ntawm q2, ces lub zog hluav taws xob ntawm lub zog them q3 yog… (1 µC = 10-6 C)
A. 4,6 x 107 NC-1
B. 3,6 x 107 NC-1
C. 1,6 x 107 NC-1
D. 1,4 x 107 NC-1
E. 1,3 x 107 NC-1
Kev Sib Tham
Them q3 muab tso rau ntawm qhov deb ntawm 5 cm ntawm q2, lub ntsiab lus tsis nyob rau sab laug ntawm q2 tab sis ntawm sab xis q2Yog tias nyob rau sab laug q2 ces qhov hluav taws xob tshwm sim yog xoom. Qhov no yog vim qhov kev ncua deb ntawm cov nqi q3 nrog lub zog q1 thiab q2 yog 5 cm thiab qhov loj ntawm lub nqi yog q1 sib npaug rau tus nqi q2.
Vim tias tus nqi q 3 yog qhov zoo, qhov kev taw qhia ntawm lub zog hluav taws xob ntawm tus nqi q 3 yog mus rau tus nqi tsis zoo q 2 (E 2 ) thiab deb ntawm tus nqi zoo q 1 (E 1 ). Lub zog hluav taws xob tshwm sim yog qhov sib sau ua ke ntawm lub zog hluav taws xob E 1 thiab E 2.
Nws yog paub :
Them q1 = 5 µC = 5 x 10-6 Coulomb
Them q2 = 5 µC = -5 x 10-6 Coulomb
Qhov nrug ntawm cov nqi q1 thiab them q3 (r1) = 15 cm = 0,15 m = 15 x 10-2 'meter'
Qhov nrug ntawm cov nqi q2 thiab them q3 (r2) = 5 cm = 0,05 m = 5 x 10-2 'meter'
k = 9 x 109 N m2 C-2
Nug Lub zog ntawm lub zog hluav taws xob thaum them q3
Jawb :
Lub zog hluav taws xob 1
E1 = kq1 / r ib12
E1 = (9 x 109)(5 x 10-6) / (15 x 10-2)2
E1 = (45 x 103) / (225 x 10-4)
E1 Luas = 0,2 x 107 N / C
Lub zog hluav taws xob 2
E2 = kq2 / r ib22
E2 = (9 x 109)(5 x 10-6) / (5 x 10-2)2
E2 = (45 x 103) / (25 x 10-4)
E2 Luas = 1,8 x 107 N / C
Lub zog hluav taws xob tshwm sim
Lub zog hluav taws xob tshwm sim ntawm qhov them q3 yog:
E = E2 - E1 = (1,8 x 107)–(0,2 x 107) = 1,6 x 107 N / C
Lub zog hluav taws xob yog mus rau sab laug los yog nyob rau hauv lub zog E2.
Cov lus teb yog C.
16. Ob lub zog hluav taws xob raug cais raws li qhia hauv daim duab. Lub zog ntawm lub zog ntawm qhov chaw P yog… (k = 9 x 109 N m2 C-2)
A. 9,0 x 109 NC-1
B. 4,5 x 109 NC-1
C. 3,6 x 109 NC-1
D. 5,4 x 109 NC-1
E. 4,5 x 109 NC-1
Kev Sib Tham
Nws yog paub :
Them qA = +2,5 C
Them qB = -2 C
Qhov nrug ntawm cov nqi qA thiab qhov chaw P (rA) = 5 m
Qhov nrug ntawm cov nqi qB thiab qhov chaw P (rB) = 2 m
k = 9 x 109 N m2 C-2
Nug Lub zog hluav taws xob ntawm qhov chaw P
Jawb :
Lub zog hluav taws xob A
EA = kqA / r ibA2
EA = (9 x 109)(2,5) / (5)2
EA = (22,5 x 109) / 25 tauj
EA Luas = 0,9 x 109 N / C
Lub zog hluav taws xob B
EB = kqB / r ibB2
EB = (9 x 109)(2) / (2)2
EB = (18 x 109) / 4 tauj
EB Luas = 4,5 x 109 N / C
Lub zog hluav taws xob tshwm sim
Lub zog hluav taws xob tshwm sim ntawm qhov chaw P yog:
E = EB - EA = (4,5 – 0,9) x 109 Luas = 3,6 x 109 N / C
Lub zog hluav taws xob yog mus rau sab laug los yog nyob rau hauv lub zog EB.
Cov lus teb yog C.
17. Ob lub nqi hluav taws xob txhua tus muaj ib qho nqi Q.1 = -40 µC thiab Q2 = +5 µC nyob rau ntawm qhov chaw raws li qhia hauv daim duab (k = 9 x 109 Nm2.C-2 thiab 1 µC = 10-6 C), lub zog hluav taws xob ntawm qhov chaw P yog ...
A. 2,25 x 106 NC-1
B. 2,45 x 106 NC-1
C. 5,25 x 106 NC-1
D. 6,75 x 106 NC-1
E. 9,00 x 106 NC-1
Kev Sib Tham
Nws yog paub :
Them q1 = -40 µC = -40 x 10-6 C
Them q2 = +5 µC = +5 x 10-6 C
Qhov nrug ntawm cov nqi q1 thiab qhov chaw P (r1) = 40 cm = 0,4 m = 4 x 10-1 m
Qhov nrug ntawm cov nqi q2 thiab qhov chaw P (r2) = 10 cm = 0,1 = 1 x 10-1 m
k = 9 x 109 N m2 C-2
Nug Lub zog hluav taws xob ntawm qhov chaw P
Jawb :
Lub zog hluav taws xob 1
E1 = kq1 / r ib12
E1 = (9 x 109)(40 x 10-6) / (4 x 10-1)2
E1 = (360 x 103) / (16 x 10-2)
E1 Luas = 22,5 x 105 N / C
Lub zog hluav taws xob 2
E2 = kq2 / r ib22
E2 = (9 x 109)(5 x 10-6) / (1 x 10-1)2
E2 = (45 x 103) / 1 x 10-2
E2 Luas = 45 x 105 N / C
Lub zog hluav taws xob tshwm sim
Lub zog hluav taws xob tshwm sim ntawm qhov chaw P yog:
E = E2 - E1 = (45 – 22,5) x 105 Luas = 22,5 x 105 N / C
E = 2,25 x 106 N / C
Lub zog hluav taws xob yog mus rau sab xis los yog nyob rau hauv lub zog E2.
Cov lus teb yog lawm yog A.
18. Ob lub nqi hluav taws xob raug muab tso rau nyias raws li qhia hauv daim duab. Lub nqi ntawm A yog 8 µC thiab lub zog rub uas ua rau ob lub nqi yog 45 N. Yog tias lub nqi A raug txav mus rau sab xis los ntawm 1 cm thiab k = 9.109 Nm2.C-2ces lub zog uas ua rau ob lub zog ntawd...
A. 45 N
B. 60 N
C. 80 N
D. 90 N
Sab Hnub Tuaj 120 N
Kev Sib Tham
Nws yog paub :
Lub zog hluav taws xob ntawm A (q)A) = 8 µC = 8 x 10-6 Coulomb
Lub zog hluav taws xob ntawm ob lub nqi (F) = 45 Newton
Qhov nrug ntawm ob lub nqi (r)AB) = 4 cm = 0,04 meters = 4 x 10-2 'meter'
Qhov tsis hloov pauv (k) = 9 x 109 Nm2.C-2
Nug Lub zog hluav taws xob ntawm ob lub nqi yog tias lub nqi A raug txav mus rau sab xis los ntawm 1 cm lossis 0,01 meters
Jawb :
Ua ntej xam qhov hluav taws xob ntawm B, tom qab ntawd xam lub zog hluav taws xob ntawm ob qhov hluav taws xob, yog tias qhov hluav taws xob ntawm A raug txav mus rau sab xis los ntawm 1 cm.
Lub zog fais fab ntawm B :
Coulomb txoj cai lij choj qauv :
F = k (q)A)(qB) / r2
F r2 = k (q)A)(qB)
qB = F r2 / k (qA)
Lub zog fais fab ntawm B :
qB = (45)(4 x 10-2)2 / (9 x 109)(8 x 10-6)
qB = (45)(16 x 10-4) / 72 x 103
qB = (720 x 10-4) / (72 x 103)
qB Luas = 10 x 10-7 Coulomb
Lub zog hluav taws xob ntawm cov nqi hluav taws xob A thiab B :
Yog tias tus nqi ntawm A raug txav mus rau sab xis los ntawm 1 cm, qhov kev ncua deb ntawm ob tus nqi dhau los ua 3 cm = 0,03 meters = 3 x 10-2 'meter'
F = k (q)A)(qB) / r2
F = (9 x 109)(8 x 10-6)(10 x 10-7) / (3 x 10-2)2
F = (9 x 109)(80 x 10-13) / (9 x 10-4)
F = (1 x 109)(80 x 10-13) / (1 x 10-4)
F = (80 x 10-4) / (1 x 10-4)
F = 80 Newtons
Cov lus teb yog C.
19. Ob lub zog fais fab P thiab Q uas sib nrug deb 10 cm muaj lub zog nyiam 8 N. Yog tias lub zog Q txav mus rau lub zog P (1 µC = 10-6 C thiab k = 9 x 109 Nm2.C-2), ces lub zog hluav taws xob uas tshwm sim yog...
A. 8 N
B. 16 N
C. 32 N
D. 40 N
Sab Hnub Tuaj 56 N
Kev Sib Tham
Nws yog paub :
Qhov nrug ntawm cov nqi P thiab Q (r)PQ) = 10 cm = 0,1 m = 1 x 10-1 m
Lub zog hluav taws xob ntawm cov nqi P thiab Q (F) = 8 N
Lub zog hluav taws xob Q (qQ) = 40 µC = 40 x 10-6 C
Qhov tsis hloov pauv (k) = 9 x 109 Nm2.C-2
Nug Lub zog hluav taws xob ntawm cov nqi P thiab Q yog tias cov nqi Q raug txav mus rau cov nqi P 5 cm
Jawb :
Ua ntej, xam qhov hluav taws xob P, tom qab ntawd xam lub zog hluav taws xob ntawm ob lub hluav taws xob, yog tias lub hluav taws xob Q txav mus rau qhov hluav taws xob P 5 cm.
Lub zog hluav taws xob P :
qP = F r2 / k (qQ)
qP = (8)(1 x 10-1)2 / (9 x 109)(40 x 10-6)
qP = (8)(1 x 10-2) / 360 x 103
qP = (8 x 10-2) / (36 x 104)
qP = (1 x 10-2) / (4,5 x 104)
qP = (1/4,5) x 10-6 Coulomb
Lub zog hluav taws xob ntawm cov nqi hluav taws xob P thiab Q :
Yog tias tus nqi ntawm Q raug txav mus rau sab laug los ntawm 5 cm, qhov kev ncua deb ntawm ob tus nqi dhau los ua 5 cm = 0,05 meters = 5 x 10-2 'meter'
F = k (q)P)(qQ) / r2
F = (9 x 109)( (1/4,5) x 10-6)(40 x 10-6) / (5 x 10-2)2
F = (2 x 103)(40 x 10-6) / (25 x 10-4)
F = (80 x 10-3) / (25 x 10-4)
F = 3,2 x 101
F = 32 Newtons
Cov lus teb yog C.
20. Saib daim duab hauv qab no ntawm lub zog hluav taws xob. Lub zog hluav taws xob uas lub zog q raug yogB yog 8 N (1 µC = 10-6 C) thiab (k = 9.109 Nm2.C-2). Yog tias tus nqi qB txav mus rau 4 cm ntawm A, ces lub zog hluav taws xob uas tau ntsib yog qB tam sim no yog…
A. 2 N
B. 4 N
C. 6 N
D. 8 N
Sab Hnub Tuaj 10 N
Kev Sib Tham
Nws yog paub :
Qhov nrug ntawm cov nqi A thiab B (r)AB) = 2 cm = 0,02 m = 2 x 10-2 m
Lub zog hluav taws xob ntawm cov nqi A thiab B (F) = 8 N
Lub zog hluav taws xob A (qA) = 2 µC = 2 x 10-6 C
Qhov tsis hloov pauv (k) = 9 x 109 Nm2.C-2
Nug Lub zog hluav taws xob ntawm cov nqi A thiab B yog tias qhov deb ntawm ob lub nqi yog 4 cm
Jawb :
Ua ntej, xam lub zog fais fab B, tom qab ntawd xam lub zog fais fab ntawm ob lub zog fais fab yog tias qhov deb ntawm ob lub zog fais fab yog 4 cm = 0,04 meters = 4 x 10-2 meter
Lub zog fais fab B :
qB = F r2 / k (qA)
qB = (8)(2 x 10-2)2 / (9 x 109)(2 x 10-6)
qB = (8)(4 x 10-4)/ (18 x 103)
qB = (32 x 10-4) / (18 x 103)
qB = (32/18) x 10-7
qB = (16/9) x 10-7 Coulomb
Lub zog hluav taws xob ntawm cov nqi A thiab B :
F = k (q)A)(qB) / r2
F = (9 x 109)(2 x 10-6)( (16/9) x 10-7) / (4 x 10-2)2
F = (18 x 103)( (16/9) x 10-7) / (16 x 10-4)
F = (2 x 103)(16 x 10-7) / (16 x 10-4)
F = (2 x 103)(1 x 10-7) / (1 x 10-4)
F = (2 x 10-4) / (1 x 10-4)
F = 2 Newtons
Cov lus teb yog lawm yog A.
Qhov chaw nug lus:
Cov Lus Nug Txog Kev Xeem Physics Hauv Tebchaws Rau Tsev Kawm Ntawv Theem Siab/Tsev Kawm Ntawv Theem Siab Ua Haujlwm
