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习题练习:Physics Unit21: Electromagnetic Induction & Faraday's Law



 作者: admin   总分: 142分  得分: _____________

答题人: 匿名未登录  开始时间: 22年08月20日 21:29  切换到: 整卷模式

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1#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  All of the following are unu qc: pm.6ki3 (o8zgofits of magnetic flux except

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2#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Faraday's law of induction stp8*lh0zksbp s ws2v r1,3dw-.hih(zfates that the $emf$ induced in a loop of wire is proportional to

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3#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Doubling the number of loops of wir)vlmir s+3pxq 0f2s(a9 r3trre in a coil produces what kind of change on the ind rfpt+9vlmr2 srqa0(3xr)3 si uced $emf$, assuming all other factors remain constant?

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4#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Doubling the strength of the magnetic fo;8 nasin:lvj8h* -ahield through a loop of wire produces what kind of change onnva*8n;- 8:o ihhjasl the induced $emf$, assuming all other factors remain constant?

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5#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Doubling the diameter6avxt3 cq ( hcsv d 0pb4f+awm87*9uvx of a loop of wire produces what kind of change on the inducedcxuvhdb 0q+avfx* a78 sm9tw (p46c 3v $emf$, assuming all other factors remain constant?

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6#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  As a coil is removed from a magnetic field pf.2,6lsoly svg 8:8bzt8zkx an $emf$ is induced in the coil causing a current to flow within the coil. This current interacts with the magnetic field producing a force which

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7#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  According to Lenz's law, the direction of an induced current in a xj8hu/ g4hr6:u sy-. op04x plh cuix5conductor will be that which tends to produceu8- hyhpgcu:x x0 p5ihj46 slou/ r4.x which of the following effects?

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8#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A circular coil lies flat on p406 izxusr3aa horizontal table. A bar magnet is held above its center with its north pole pointing down. The stationary magnet indux34s au0rzp6ices (when viewed from above)

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9#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A circular coil lies flat on a horizontal table. A bar magneg *eg:qp/ t;ko0nkzx p18o7 dyt is held above its center with its north pole pointing down, and releasent gookxdg08p 7kp*ezq:;1 y/d. As it approaches the coil, the falling magnet induces (when viewed from above)

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10#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A coil lies flat on a table top in a region where the magnetic field kla/wgt3v 9l ;vector points straight up. The magnetic field vanishes suddenly. When viewed from above, whv3 ;lw/kt9la gat is the sense of the induced current in this coil as the field fades?

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11#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A coil lies flat on a level table top in a region where/znxl4ifyh ,h +a;yjz829k .8lptczp the magnetic field vector points straight up. The magnetic field suddenly grows stronger. When viewed from above, what is the direction of the induced current in this zyh/ 2 98l4pt l;.kx,zcp+fnjiah yz8coil as the field increases?

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12#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A coil lies flat on a horizontal table top in a region whe-,e,ae7( swohwrm .o8mno(xsre the magnetic field points straiwm8( m.ooh,serwo(-7n sa,x eght down. The magnetic field disappears suddenly. When viewed from above, what is the direction of the induced current in this coil as the field disappears?

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13#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A long straight wire lies on a horizontal table and carries az5au(fs/fvi31 5o jtan ever-increasing current northward. Two coils of wire lie flat on the table, one on either side of the wire. When viewed from above, the induced current circle1ofts 5ia z5aj fuv3/(s

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14#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A bar magnet falls through qf,gop a4zmn4 *:c7nja loop of wire with the north pole entering first. As the north pol:caqjnz g 4,o4f7npm*e enters the wire, the induced current will be (as viewed from above)

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15#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A circular loop of wishi oh ,t+4wobwnqk +d4*j-.lre is rotated at constant angular speed about an axis whose direction can be varied. In a region where a uniform magnetic field points straight down, what must be too j *+d4ishhw. n-,l b4wqt+khe orientation of the loop's axis of rotation if the induced $emf$ is to be zero?

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16#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A circular loop of wire is rotated at constant angular sp3rj*c2 ou(igs- 5sn fbeed about an axis whose direction can be varied. In a region where a uniform magnetic field points straight down, what must be the orientatio* fr( 3cg-nu 2b5ssijon of the loop's axis of rotation if the induced $emf$ is to be a maximum?

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17#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
State Faraday's law.x:7 kd f;.bdqn3z 5o2v9jl nps
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18#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
State Lenz's law.
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19#
 
问答题 ( 1.0 分) 切至整卷模式 搜藏此题  
List the three ways thatliqu5 *w+9gq:2xe utn an $emf$ can be induced in a loop of wire.
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20#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A wire moves across a magnetic field. ggrax 9(y9o l)The $emf$ produced in the wire depends on

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21#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A horizontal rod (orieulhq2 zm6pf*)jn 5y0qnted in the east-west direction) is moved northward at constant velocity through a magqylhupnf jq m650 )z*2netic field that points straight down. Make a statement concerning the potential induced across the rod.

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22#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A horizontal metal bar rotates at a constant ao 9 w;yjp o-l(swh(m26ljk)ybngular velocity $\omega$ about a vertical axis through one of its ends while in a constant magnetic field B that is directed down. The $emf$ induced between the two ends of the bar is

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23#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An electric generator transfoeufzl r41-(lqx l9mj*rms

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24#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A generator coil rotates through 60 revolutions each second. The (uknzu5ghh *.a;c+ bb frequency of the (k5gh+.b *uanbcz h ;u$emf$ is

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25#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A transformer is a devic kp 2 )myize*5:oltveb+(pf 9se used to

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26#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A transformer is a devit.blkzruq2 b5j:u8ri 4r tm r:s6x22jce that

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27#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In a transformer, if the secondary coil cv+ laym2aqtuods le5- ) 5u67yontains more loops than the primary coil then it issa5 u2 tdm6-loq+ av yel)u7y5 a

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28#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In a transformer, if the primary coil contains more loops than the seco(14wzg tbxcg2ndary coil then4xb gw21g(ztc it is a

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29#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In a transformer, the power iy5tpht* uo3u4*k mva7nput

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30#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In a given LC resonant cir ttmsw6z y0)-lcuit,

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31#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A resistor and an inductor are connected in sekr28b gmuj1-j ubo.a 2ries to an ideal battery of constant terj 1u-j2mour2bg b.8kaminal voltage. At the moment contact is made with the battery, the voltage across the resistor is

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32#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A resistor and an inqhtynz8+i3w e+3v l.dductor are connected in series to an ideal battery of constant terminal voltage. At the moment contact is made with the battery, the voltage across the inductor isd q3 +yne+l 3.htwv8iz

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33#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A series RL circuit with inductance L and resistance R is connected elf. 0,)wt(rx- sngh pto an $emf$. After a period of time, the current reaches a final value of 2.0 A. A second series circuit is identical except that the inductance is 2L. When it is connected to the same $emf$, what will be the final value of the current?

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34#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A series RL circuit with inductan ;dmaur5v2 0rdce L and resistance R is connected to an $emf$. After a period of time, the current reaches a final value of 2.0 A. A second series circuit is identical except that the resistance is 2R. When it is connected to the same $emf$, what will be the final value of the current?

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35#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A resistor and an inductor are connected in series to a battery. The ts5vr.-cr;e8,g ztb :abevor2, (wg kfime constant for the circuit represg r.c,;brsav kz2fbv8( : otgw5e e,-rents the time required for the current to reach

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36#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A resistor and an inductor are connected in series to a battery. The batte5 7z9q*hy;u7 0pr2 psoyf bctery is suddenly removed from the circuit. The time constant for of the circuit represents the time requireo yqt57u7 *b2 r hfp0py;ec9zsd for the current to decrease to

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37#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  All of the following have the same units exc6 ,zy yalgss3n+ 74trmept:

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38#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A resistor is connec7q c0f*+h -2gdm,gc unn2mqdh ted to an AC power supply. On this circuit, the current

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39#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A pure inductor is connected to an AC power nk -vp*6g: xbx7 yd.bwy8)zyasupply. In this circuit, the current.naywyb-g7k:y8xd)6b z x*vp

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40#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The inductive reactance in anr psn *wa x)vk2s.;r zp+3+eeb ac circuit changes by what factor when the frequency r *;n 3wxb. p)svsr2a+ee+kpz is tripled?

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41#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If the frequency of the AC voltage acrhk2j pl;t z9n)oss an inductor is doubled, the inductive reactance z2p;hkl 9jtn)of that inductor

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42#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  As the frequency of the AC voltage ac da3otc(;k5ws:m+ ah fross an inductor approaches zero, the inductive reactance of that coi;3a+a :ohcd5wk smft(l

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43#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A pure capacitor is connected to an zw eggjs.k8098v 4wqb AC power supply. In this circuit, the currevz.wk0884bgwqs9 g e jnt

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44#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The capacitive reactance inlqb x;n1rbg;d5( 9/plniai 1 p an ac circuit changes by what factor when the frequency is tripled?g;1p/95x al1bni(rld bq;ipn

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45#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  As the frequency of the AC voltage across a capacitor approaches zero, the capfvbeh,q,)p t ;aci,pftv;qh )be, tive reactance of that capacitor

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46#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the phase angle between tbq3i/ d1hjmu1 ,wm9y. gudah5he voltages of the inductor and capacitor in a RLC series circuit /yma 9im5dw11 dh3jhuq.u,gb?

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47#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The power factor of an RLC circuit i pb/hoh ev f:xk :*ozn7xti:84ks)ep2 s defined as $\cos M = R/Z$, but the phase angle can also be calculated from .

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48#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider an RLC circui2hn3scfa- dv2yu00c o t. The impedance of the circuit increases if R increases. When is this sy2 vf0 0nhdo3- uacsc2tatement true?

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49#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider an RLC circuit. The imped1 ea+8trpp*i v jynhe9 d9a6l-ance of the circuit increases if $X_L$ increases. When is this statement true?

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50#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider an RLC series circuit. cd-9p waw9 vwtxz.* )mw)y,zo The impedance of the circuit increases if $X_C$ increases. When is this statement true?

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51#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If the inductance and the capacitance both double in an LRC series circu1 5 *hqfah(ac rz5y2ir/e 7yoait, the resonay /5 1( raq7e5oazac2*fyhrh int frequency of that circuit will

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52#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider an RLC circuit that is driven by an AC applied xfowwz sl)n4w3 n9y86loa6 4 svoltage. At resonance,

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53#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Resonance in a series RLC circuit oc-+uc2f ti ,qsog ;dvq+curs when

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54#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A flux of $4.0 \times 10^{-5} \; Wb$ is maintained through a coil for 0.50 s. What $emf$ is induced in this coil by this flux?

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55#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A circular loop of radius 0.10 m is rotating ahck;8,j9y wnlr-s d/in a uniform magnetic field of 0.20 T. Find the maglc-k rda h;, j8sw/ny9netic flux through the loop when the plane of the loop and the magnetic field vector are parallel.

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56#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A circular loop of radius 0.10 m is rotating in a uniform magnetic. j qu*mwpk0,n field of 0.20 T. Find the magnetic flux through the loop when the plane of the loop and the magnetic field vw*,j. uq0nkpm ector are perpendicular.

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57#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A circular loop of radius 08 c ui. z9zwhfcr5xrdo, xz4*3.10 m is rotating in a uniform magnetic field of 0.20 T zwoi dz3cx45,f*rxcz.u8r h9. Find the magnetic flux through the loop when the plane of the loop and the magnetic field vector are at an angle of $30^{\circ}$.

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58#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The cross-sectional area 81l1wda3 rhscof an adjustable single loop is reduced from $1.0 \; m^{2}$ to $0.50 \; m^{2}$ in 0.10
s. What is the average $emf$ that is induced in this coil if it is in a region where B = 2.0 T upward, and the coil's plane is perpendicular to B?

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59#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The flux through a co8fn w 7cy;6nspil changes from $4.0 \times 10^{-5} \; Wb$ to $5.0 \times 10^{-5} \; Wb$ in 0.10 s. What $emf$ is induced in this coil?

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60#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A coil is wrapped with 200 turns of wire on a square fwgjer lmbma 9moi a,)ya 86(4.x+j8hy rame with sides 18 cm. A uniform magnetic field is applied perpendicular to the pilx(mj gm8)a9.yer a o y4wam8hjb6,+ lane of the coil. If the field changes uniformly from 0.50 T to 0 in 8.0 s, find the average value of the induced $emf$.

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61#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A square coil of wire with 15 turns and an area of q xs7x1cf+po wq 2u+0q$0.40 \; m^{2}$ is placed parallel to a magnetic field of 0.75 T. The coil is flipped so its plane is perpendicular to the magnetic field in 0.050 s. What is the magnitude of the average induced $emf$?

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62#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A coil of 160 turns h8y2q jqt+fx xxkj (*/(2a yefand area $0.20 \; m^{2}$ is placed with its axis parallel to a magnetic field of 0.40 T. The magnetic field changes from 0.40 T in the x-direction to 0.40 T in the negative x-direction in 2.0 s. If the resistance of the coil is 16 W, at what rate is power generated in the coil?

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63#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An airplane with a wing span of 60 m flies horizontally at a locn rkto:xtvfi iw;z6d,9d-i-*ation where the downward component of the Earth's magnetic field is nrw -f: d t9tvd;*ixzik-o,i 6$6.0 \times 10^{-5} \; T$. Find the magnitude of the induced $emf$ between the tips of the wings when the speed of the plane is 225 m/s.

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64#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A horizontal metal bar that is 2.0 m long rotates at f q 6f2yzn4s6ea 4g-u bywah4-a constant angular velocity of 2.0 rad/s about a vertical axis through one of its ends while in a constant magnetic field o4fyw4 -b-fn64sua2yazge q6hf $5.0 \times 10^{-5} \; T$. If the magnetic field vector points straight down, what $emf$ is induced between the two ends of the bar?

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65#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The coil of a generator has 50 loops and a cross-sectional areat3ft: yyh/ rfv+) 2xmv of $0.25 \; m^{2}$. What is the maximum $emf$ generated by this generator if it is spinning with an angular velocity of 4.0 rad/s in a 2.0 T magnetic field?

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66#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An AC generator consi uq tfzyio)o9 pvf*71+sts of 100 turns of wire of area $0.090 \; m^{2}$ and total resistance 12 W. The loops rotate in a magnetic field of 0.50 T at a constant angular speed of 60 revolutions per second. Find the maximum induced $emf$.

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67#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An AC generator has 80 rectangular loops on its armature. Eacba+-7ohxt0c kfo;p q0h loop is 12 cm long and 8 cm wide. The armature rotates at 1200 rpm about an axis paraqbph 0;ot7+o0x-f ac kllel to the long side. If the loop rotates in a uniform magnetic field of 0.30 T, which is perpendicular to the axis of rotation, what will be the maximum output voltage of this generator?

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68#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An AC generator consists of 100 turns of wire .7qkv1p 8lq/sxru 6ma98 r tmdof area $0.090 \; m^{2}$ and total resistance 12 W. The loops rotate in a magnetic field of 0.50 T at a constant angular speed of 60 revolutions per second. Find the maximum induced current.

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69#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Suppose that you wish to construct a si)kr)q uj;0ees lb:0 /rsd*qemmple AC generator with an output of 12 V maximum when rotated at 60 Hz. A magnetic field of 0.050 um0k:*)ers b;ree sj /)q0ld qT is available. If the area of the rotating coil is $100 \; cm^{2}$, how many turns are needed?

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70#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  You are designing a generator with a maxi-aicgb l) 21xsdcgf5j:(z( 6jlh5gmb mum $emf$ of 8.0 V. If the generator coil has 200 turns and a cross-sectional area of $0.030 \; m^{2}$, what would be the frequency of the generator in a magnetic field of 0.030 T?

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71#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The windings of a DC motor have a resistance of 6.00 W. The motor g aw 6l9wfs8lidv2- 9n7amqm2 operates on $120 \; V$ AC, and when running at full speed it generates a back $emf$ of 105 V. What is the starting current of the motor?

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72#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The windings of a DC motor have a resistance of 6.00 W. xbc91 8znrp/bt, fvah 81udk/ The motor operates on 120 V AC, and when1 u9 d1r/bhf ,ptk /vc8bx8nza running at full speed it generates a back $emf$ of 105 V. What current does the motor draw when operating at full speed?

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73#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A DC motor of internal resistance 6.0 W is connected to a 24-V power supply. fv. /+igjn/qpef2-o7s:f kpc The operatp:g/ 2- k7jsfe+/ffqin ov.pcing current is 1.0 A. What is the start-up current?

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74#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A DC motor of internal resistance 6.0 W is connecvaor8nh74:+ez np mo+ted to a 24-V power supply. The operating current is 1.0 A at full speed. What is tnn h:p +7 8+moz4aoevrhe back $emf$ when the motor is running at full speed?

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75#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A DC motor of internal res,0*pfwkf9 35po1 uv7y bigo 8;sedovvistance 6.0 W is connected to a 24-V power supply. The ov1ob; *vd7pg v ,ysfeo8uwop03i5kf9perating current is 1.0 A at full speed. What is the back $emf$ when the motor is running at half speed?

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76#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A step-down transformer is needed tg2u470 dbvqm .zc(vuu+ n a6vwh()ppto reduce a primary voltage of $120 \; V$ AC to $6.0 \; V$ AC. What turns ratio is required?

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77#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  2.0 A in the 100-turn primary of a transformer causes 14ish:en+ad6o/cz,(ve vg901 v*oyk 6 e.junhs A to flow in the secondary. How many turns.9esh:za6o n(kd0 y j1/uhve e*ig v+con6s,v are in the secondary?

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78#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In a transformer, how many turns are necessary in a 110-V primary if the 248vkt /;z0jxb g-V secondart v; 8kbxg/0zjy has 100 turns?

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79#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An transformer consists of a 500-turn primary coil and a 20pvg14b n91mif00-turn secondary coil. If the current in the secondary p1 mgf1in49vb is 3.0 A, what is the current in the primary?

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80#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  5.0 A at 110 V flows in the primary of a transf degtm(pw d9 1;k2fm5former. Assuming 100% efficiency, how many amps at 24 V can flow in the secon9d k(fg ;mme2p15 twdfdary?

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81#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The secondary coil of a neon sign transform)yv p(rjm5/o itj 4oe0er provides 7500 V at 10.0 mA. The primary coil operates on 120 V. What does th( pej /5 40ovjrto)miye primary draw?

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82#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An ideal transformer has 60 turns on itg2 vi3wc cp1h6dcsb9-s primary coil and 300 turns on its secondary coil. If2-b93wiscdc6p c 1hvg 120 V at 2.0 A is applied to the primary, what voltage is present in the secondary?

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83#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An ideal transformertip 1r l :8)ro ap5y654f(mh, olpu3gbpzmrm7 has 60 turns on its primary coil and 300 turns on its secondary coil. If 120 V at 2.0 A is applied to the primary, what current is presenomo7 )z54 m3:b1r 6lr rlh5 upp(,i8mpfpatgyt in the secondary?

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84#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The primary of a transformer has 100 c6x +hthkhl ctsq;ij 79q8i.0turns and its secondary has 200 turns. If the input current at the primary is 100 A, we can expect the output cur 7.;x6hi8 q lscti+hh9jqc tk0rent at the secondary to be

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85#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The primary of a transformer has f tuh,dd xb /d-0wa*8( hef3sx100 turns and its secondary has 200 turns. If the input voltasatf0x/hed3 xu,(*8dhwfb -d ge to the primary is 100 V, we can expect the output voltage of the secondary to be

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86#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The primary of a transformer has (7husmxssc 0ea.3.ry 100 turns and its secondary has 200 turns. If the power input to the primary is 10yau.mexh rs0s s(73c.0 W, we can expect the power output of the secondary to be (neglecting frictional losses)

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87#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A generator produces 60 A of current at 120 V. The voltage is u djg6 k6aa v7wac--b,3 isc1zwsually stepped up to 4500 V by a transformer and transmitted through a power line of total resistance 1.0 W. Find the number of turns in the secondary if the primary gcva6d1zj6ak-7ibca w s,3w - has 200 turns.

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88#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A generator produces 60 A of current at 120 V. The volt(5ko(jvku jw7p4c 1jb5wb n2tage is usually stepped up to 4500 V by a transformer and tran1jv ub(kwb j(ko 5pw7 njt2c45smitted through a power line of total resistance 1.0 W. Find the percentage power lost in the transmission line.

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89#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A generator produces 60 A of current at 120 Vmgg d5n x,g,eq/01vx ki8b,xs. The voltage is usually stepped up to 4500 V by a transformer and transmitted through a power line of total resistance 1.0 W. Find the percentage power lost in the transmission li0x b5,sgxxdvkm/i eg8 gn,,1 qne if the voltage is not stepped up.

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90#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A power transmission line 50 km long tcg*q8zsij6zpn/ e:)s;oz )ohas a total resistance of 0.60 W. A generator produces 100 V at 70 A. In order to reduce energy loss due to heating of the transmission line, the voltage is stepped up with a transforc) * / zs8p6ojz:zeqi;sgo tn)mer with a turns ratio of 100:1. What percentage of the original energy would be lost if the transformer were not used?

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91#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A power transmission line 50 km long has a total resistance of 0.60r*kccmw nz7k+4 -g9pd W. A generator produces 100 V at 70 A. In order to redkw - d4mzr9+k*ccng7puce energy loss due to heating of the transmission line, the voltage is stepped up with a transformer with a turns ratio of 100:1. What percentage of the original energy is lost when the transformer is used?

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92#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  100 kW is transmitted down a 6-W line at 1000 V. How much less power 7 eh9imrs)e.k would be losts me9 irh.7)ke if the power were transmitted at 3000 V instead of at 1000 V?

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93#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The output of a generator is 440 V at 20 A. It is t0:*g mz.sf4fm p.uf oro be transmitted on a line with resistance of 0.60 W. To what voltage must the generator output be stepped up with a transformer if the powe mp*s:g0.mro.f fzuf4r loss in transmission is not to exceed 0.010% of the original power?

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94#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 4.0-mH coil carries a current of 5.0 A. How much energy is stored vz:n24og k/uatrdane on-7)e qg8,e; in the coil's magnetik8artu /n dngvo7 )n2e;aee o 4qg-z:,c field?

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95#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A simple RL circuit contains a 6.0ig3 ujvmx:.m (dq j;,aw o6jm0-W resistor and an 18-H inductor. What is this circuitvqmu j:j6jg,mxd0.(io mw a3 ;'s time constant?

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96#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the peak voltage in an AC circuit where t -9opuxm*l-e rm *;kenhe rms voltage is 120 V?

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97#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 150-W lamp is placed iq(j,m:nq 2dmwnto a 120-V AC outlet. What is the peak current?

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98#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 150-W lamp is placed into a 12ts1/l4ot +5s:btst djrq iyr 77;tc.d 0-V AC outlet. What is the resistance of the lamp;.sd 7t4b5+rc:sd1o st/rl qt7 ytjti?

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99#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 10-W resistor is coi/lb 1l1)1 ezmo zu bl3ic7bti m9b/o/nnected to a 120-V ac power supply. What is the peak current through the resl1/m7lmi l ctzo31obb1e/ b 9z )/ibiuistor?

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100#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 10-W resistor is connected to a 120-V ac p+3y+1 qr(rkf jf,easu-zk id/ower supply. What is the power dissipated in the resistdj, /ku q1e+fyi zr3a+r -sk(for?

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101#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The current through a 50-W resistor ist - y ,tpis,o12pbg4ik $I = 0.80 \sin (240 t)$. What is the rms current?

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102#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The current through abpb 2b7hi /ptrout yf27m x )0pkeh,;( 50-W resistor is $I = 0.80 \sin (240 t)$. At what frequency does the current vary?

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103#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The current through a 50-W 1pan1bdx 16bsk ws6g7f.sz w*8:x zdo resistor is $I = 0.80 \sin (240 t)$. How much power on average is dissipated in the resistor?

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104#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the reactance of 3cf 5xm hfle72a 1.0-mH inductor at 60 Hz?

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105#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the inductive reactance of a 2.50-mH coil at co +zolj ,nn)u3pfl3* 1000 Hz?

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106#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  At what frequency will a 14.0-mH coil have 14.0 W ofp1 4 akiv4z1.aodlzu4 inductive reactance?

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107#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What inductance is necessary for 157 W of i v z rml5q,,lr;/xnnn x93ubp4nductive reactance at 1000 Hz?

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108#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What current flows in a 60-mH inductor when 120 V AC at a frequency of 207eyk-:+jayh c kHz is appliedkae+ :ch7y- jy to it?

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109#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the current through a 2.50-mqsr,+. u(kol,uhao0xH coil due to a 110-V, 60.0 Hz source?

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110#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the capacitive reactance of a 4.7-mF capacitor at iotfsk1mb k b b-5o9:+10 kHz?

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111#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What size capacitor is ne 3 bga))(wg vwz0c7hmdeded to have 50 W of capacitive reactance at 10 kHz?

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112#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  At what frequency does a 10-mF capac lt2dpvn:i j vgj. 31.)btu3of)6zpimitor have a reactance of 1200 W?

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113#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  At what frequency will the capacitive reactance of a 0.010-mF capacite ,eh-qyfw5p a9cip ((or be 100 W?fe,hcy5-p a (q9pe(wi

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114#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the current through a 0.0010-mF capacitor at 1000 Hz and 5.0w /mo82ga k)8/pmiun u V?

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115#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the impedance of an ac series circuit wb8gz*vovd3n xi*z 6 :fith 12.0 W resistance, 15.0 W inductive gzn vxo6*bd*v8 fi:z3 reactance, and 10.0 W capacitive reactance?

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116#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the total impedance at 1500 Hz if a 100-W resistmc4m4s nc e5bt2pw( /aor, 20-mH coil, and 1.0-mF capt4 (n /b csc4mm2wa5epacitor are connected in series?

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117#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the phase angle at 1500 Hz if a 100-W resistor, 20-mH coil, andpz l 01cs0w2 2/xfi cwbmqu:c( 1.0-mF capacitor are connected c/w 01il cc:0qs(uwx b2fmp2zin series?

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118#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If a 1000-W resistor is coxncu2h5: *z4nd 6u1vg k3 n+bqdaxpl+nnected in series with a 20-mH inductor, what is the impedance at 1000 p3 *g1cl xnud +:v6xnn5 bkhdau2 +4qzHz?

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119#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If a 1000-W resistor is conn8dk;6zwbv,3v e3v oklected in series with a 20-mH inductor, what is the phase anv,kodb6v8e3w3lz kv; gle at 1000 Hz?

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120#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What resistance is needemoxh5i)ozwc*j50 fe( d in a series circuit with a 20-mH coil and 1.0-mF capacitor for a total impedance of 100 W a )f*5ixo (05jowzmecht 1500 Hz?

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121#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Which of the following capacitances is needed iw:4fxk1i 7vf un series with a 100-W resistor and 15-mH coil to get a total impedance of 110 W at 2000 Hzxf1w: 4u7k ivf?

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122#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What resistance must be put in series withey;fcs9plp *:z+)hm q ,cnit0 a 450-mH inductor at 5000 Hz for a total impedance of 4 nlts;,+z09chfqp i m*ec p:y)0000 W?

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123#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What inductance must be put in series with a 118c la-cbwuzbon9 6g500-kW resistor at 1.0-MHz for a total impedance of 150 kl 9ocab-wuc1bgz 8n 65W?

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124#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 10-W resistor is connected in series with a 20-mF capacitor. What is the impv 4o6 .zud81 k40.cqb-l nucrsmgi)opedanu 1pmv. 0 ns- br6i4 l.kq8zgcc4ouod)ce at 1000 Hz?

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125#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What resistance is needed in serieswo x1eq5v)wgj x1,uhwj* nolud),4g( with a 10-mF capacitor at 1.0 kHz for a total impedance of 45 W?5ug)1hw,4o*)(on 1 euxx, vqwjdl gjw

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126#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What resistance is needed5qs-4nru0sy9cb ifa uq5 6lke3h:zjfa f9;j5 in series with a 10-mF capacitor at 1.0 kHz for a phase alasu9zy39a5 run5ff4 f;qhi 0:5qj- 6bej cksngle of $40^{\circ}$?

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127#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What capacitance is needed in series with aqiqubim h7,3 7re2c(ctyje6rfur(r,8 4 3hbc 30-W resistor at 1.0 kHz for a total impedan ,qc32 bce r mi4i7e(htr ufy3br(7qhuj,8 rc6ce of 45 W?

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128#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 10-W resistor is in series with a 100-mF capacit**st 7o 1 wgmsghb-;hjor at 120 Hz. What is the phas-m1g*wtgshj *;b7h o se angle?

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129#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What current flows at 5.0 V and 1500 Hz if a 100-W resistor, 20-mHdfv.3ad.1 vzc coil, and 1.0-mF capacitor are connecdfcz1v.d3 a.vted in series?

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130#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A series RLC circuit consists of a 100-W resistor, a 10.0-mF capacitohqo97; qb mzk-r, and a 0.350-H inductor. The circuit is coqobzh7k;q - 9mnnected to a 120-V, 60-Hz power supply. What is the rms current in the circuit?

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131#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A resistance of 55 W, a capacitor of capacitive reactance 30 W,qv6g 4jxkemy1 a*nys6d:h. j3 and an inductor of inductive reactance 30aj4 gh3s v6.j m n1yqk:eyx6*d W are connected in series to a 110-V, 60-Hz power source. What current flows in this circuit?

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132#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the phase angle for a series RLC cir/m4skk6ou g h7cuit containing a 50-W resistor, a 10-mF capacitor, and / k sukm64og7ha 0.45-H inductor, when connected to a 60-Hz power supply?

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133#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What inductance is necessary in series with a 500-W resis xs34pin xhdjs:1-ou8tor for a phase angle of d:pxj 4on-sx h1sui38 $40^{\circ}$ at 10 kHz?

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134#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A series RLC circuit has R = 20.0 W, L = 200-mH, C = 10.0-ulxk )0un 0rl mF. At what frequency should ukr x-l nl)0u0the circuit be driven in order to have maximum power transferred from the driving source?

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135#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the power output in an ac series circuit with 12.0 W resistance, 15.0 tq9:shuo+pd n+l 31x mW inductive reactance, and 10.0 W capacitive reactance, when the circuit is connected 9 ldmhs:xn13o u+tqp+to a 120-V power supply?

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136#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The phase angle of an AC circup7w1jlp8 2sg w3 yp)mhqsvl3z)1b*icp8 y ;jdit is $63^{\circ}$. What is the power factor?

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137#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  An ac series circuit has an impedance of 60 W and a resistanck.5/0c axn8r jv )ef5 rs8migbe of 30 W. What is the power factor? x8vkm)rfca5bs5 /.0in g8 rej

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138#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the power factor for a series RLC circuit containing a 50-W resistor, a kgv4d0rhr n2*10-mF capacitor, and a 0.45-H inductor, when connected to a 60-Hz powr*4nh0gv rk2d er supply?

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139#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the resonant frequency of a 1.0 - bkuv*q6wkt+b b++cm-mF capacitor and a 15-mH coil in series?btc-q++*m kwbbku 6+v

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140#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What inductance is needed in skh wqfyf1pm 2y,d s z.(.(hq(leries with a 4.7-mF capacitor for a resonant frequency of 10 k ps(mw l(q2kqy (ydfh.1.,zfh Hz?

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141#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What capacitance is needed in series with a 3.7-mH inductor for a resonantb5ojs44;j xxp5 *amv o frequen v;o4s55xjxm pbja4*ocy of 1000 Hz?

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142#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What size capacitor m3dqe9-du7 thz)ab 3roust be placed in series with a 30-W resistor and a 40-mH coil if the resonant frequency of the circuit is toro3)39tu qhea -zd bd7 be 1000 Hz?

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