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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 units urfhi(v7 mew,4bsaff 2o im5+ 8 8klx 8wep/7nof 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 states 94:p c5a5 ljwcb* kmnmthat 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 wire in a coil produces what kind of change o90k8bhv sbd3u1 jq1qon the indu0 o11 qdbkq3vsjhu 98bced $emf$, 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 field through -ufdf4)g -ypxa loop of wire produces what kind of change on the in)xyf- dgf-p4 uduced $emf$, 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 diameter of a loqvfhno, ;q)q0op of wire produces what kind of change on the inducedqvo;qnq, f)h 0 $emf$, 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 magnetie13b7q;idik5 qq kaf1 c field 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 currentr+ro2af2l 7 /wzvjvo8:x f1e l in a conductor will be that which tends to7 llrvv+oz oa22/jf1re:wf x8 produce 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 aq uhx0jl/4zoh vu2, 1k horizontal table. A bar magnet is held above its center with its north pole pointing down. The stationary magnet inhkovz,1 jhu/lqu24 0x duces (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. m*qyh 9h5u -,bcf+ar.ubt2 uyA bar magnet is held above its center with its north pole pointing down, and released. As it approaches thb5u-h, 2fq* yuy.mcahb9r+t u e 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 magnetice03szf sr y7+1tlo.c3x8 lh ur field vector points straight up. The magnetic field vanishes suddenly. When viewed from above, what is the sense of the induced current in l03lrztfx.yh u8r+ oe7 31ss cthis 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 regionspckxj z;d(/ rdxk:/ 1vt c5y+ where 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 cz/ /d1ckp cvdx; j:t(rsk +y5xoil 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 where the magnetic fiel5+qkuyif ;dgji 6o/ea3u2qf. d points straight down. The magnetic field disappears suddenly. When vieiuky/+adf jeo ;ig q2.q36fu5 wed 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 carriz,:od l f31kzo qma-nd2cd9n/es an ever-increasing current northward. Two coils of wire lie flat on the table, one on either side o,m az f dzn3o912/dqc :dnkol-f the wire. When viewed from above, the induced current circles

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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 td,cpc2e c//5k oce lm3hrough a loop of wire with the north pole entering first. As the north pole enters the wire, thedp2kcc 35/m,e eoclc/ 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 wire is rotated at constant angular speed about an tvtbr 7 lc;+-)3wujlfaxis whose direction can be varied. In a region where a uniform magneti-vucw7 r;l)t+b3 ltf jc field points straight down, what must be the 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 rotateexyym ci0t-qw/h 5 j-j q26py-d at constant angular speed about an axis whose direction can be varied. In a region where a u6e mj-iy502yxpy-c-/jq wqth niform magnetic field points straight down, what must be the orientation 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. d,*-ix ytm c8rx4ab;c
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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 that an 7z70ysw : p psme9m1ec$emf$ 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 fieldr7 hkxyst7w* : u:c)fm. 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 (oriented in the east-west di7 ; 4jrug*phmprection) is moved northward at constant velocity through a magnetic f p;47hjr p*mugield 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 angular venu0fez /y4m. m.+xw r,bicw;ylocity $\omega$ 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 transfor3+wbd. rtnen *.)csoyms

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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 se *fu+*fpi qcvozd (96y,t,baycond. The frequency of tq fdti f a+z6oyv,9p(,y*cu*bhe $emf$ 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 device used r hl /nvx-8nk 1w0ty/kto

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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 device tq wq1r d*ll9e/hat

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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 contains more loops tha3jn2+g jf6b dfn the primary coil fnb3fjj g+ 6d2then it is 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 t8 ztu8 hdn-f:whan the secondary coil then df- 88twhzn:uit 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 powebgs 0:*7smu gp6yqz4xr input

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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 circuit,bznml caj;+t(mn 6, )q

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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 series qbokuv5jo 8:epbwbk)i*.pta qpovv7 8d15 (( to an ideal battery of constant terminal voltage. At the moment co.5pk v(p a qv8q db*78kb:t)p o5bu1jovwi e(ontact 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 inductor are connected in series to an ;pue/ iots5(h ps5:gmideal battery of constant terminal voltage. At the moment contac :us5s5eppmihto g(/; t is made with the battery, the voltage across the inductor is

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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 2slh d5:rh;l yresistance 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 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 wmie7g *os 8a(jrm jm5.ith inductance 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 *w 0jdgfez,avw9 -)a 1mnu5ht in series to a battery. The time constant for the circuit represents the ti n0-5ejdahgfam z,1*wvu)9tw me 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 inducz9jt.43 0; , hra hxwp)e vhtnnnn3rk,tor are connected in series to a battery. The battery is suddev nzhen9 xhntr3akptjh,w4);,r 3n .0nly removed from the circuit. The time constant for of the circuit represents the time required 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 mygo;4 x.ei9 aexcept:

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38#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A resistor is connected to an AC power supply. On this circuit, the currentvnl9)hh 4 y)s6a.5tkw ipg kt9

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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 supply. I22vh;d kbfr 09z oip6u(wovd5n this circuit, the current09z2rbvfo(u h ;pv65i2kodd w

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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 an ac circuit changes by what factk57, aavy4abmi kdvz lo14-n.s0xte 2or when the frequency is tripled?mvkeb 5ys- t zxk oan4.4via201dal,7

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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 across an inductor is double. mtd3sgr//3kiuk qq5 d, the inductive reactance of th t5qu/kmigkr3 sd3. /qat 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 across an xvj sxg-ca1;ow l)2f,ihq 3-tinductor approaches zero, the inductivo 13;axh ),vqit fcgw2lsj --xe reactance of that coil

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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 AC power supply. In this circuit, th)t5 a1( jt49ky+rjr*f *td s zhsspyl5e currentsdfkr5ys hyzpa)5j *4(lt19*s t rj+t

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44#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The capacitive reactance in 76p +qi1wxgw;scf;pk an ac circuit changes by what factor when the frequencwp;f q1i+sxgk ;6cp7 wy is tripled?

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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 approl,ua 6b vb-xs3zt 46keaches zero, the capacitbv 3ez4u -t6l xab,k6sive 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 be6j*f6jnixo1bof 7- qihd j689xe 2qqt tween the voltages of the inductor and capacitor in a RLC se67*qd j qj -fi961ohx2itxqe8of nbj6ries circuit?

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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 aopp+36 lhh;ecircuit is 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 circuit. The impedance of the circuit increase2w 6m5 yuuph5ss if R increases. When ispu5h muy62 5ws this statement 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 impedance of uv. ir0x ot6)xthe 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. The impedance of the circuit increasenh(c; tequy2 5s 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 capacitancexp)y a5q,q,e/hji 5 wj b3jl7c- mkqx8 both double in an LRC series circuit, the resonant freque,x,iep 5/qaylq c8 wb-hkx mj7)j53 jqncy 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 voltage. 6nkdu4cafyj(dkx 4s8l 6s/6j 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 RLCvyjk-hy6ha1 82j , 0oz5yb alx circuit occurs 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 in a uniform magnet0 7kvbhvm 2ssg+0; utlic field of 0.20 T. Find the magnetic flux through the loop when the plane of the logb vs+;7mku2 th0svl0op 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( q+egzbj2l7bt1 w;lz magnetic field of 0.20 T. Find(let;2b 7z+b ljqz1 gw the magnetic flux through the loop when the plane of the loop and the magnetic field vector 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 0.10 m is rotating in a uniform magnetic field of 0./3w -4:x1a qn yoppmzmy9zif 420 T. Find the magnetic flux through the loop when the plane of the loop and the magnetic field vector are ayz93f:41 mxz nip/ a-my4wpoq t 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 of anzvn wu; c1*3mn+1.r j6n nnnnb 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 coil c /bxplc/bk( 2 k2orm;rhanges 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 frame with szgmtgfq(10y c z xl092(si pt8mpv m+jyb-r;4 ides 18 cm. A uniform magnetic field is appliedxtmbtr9qfpsgc 2;l-z (0z v j8mmy+g40p1(y i perpendicular to the plane 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 wireqfrqp y1 3v))y3 9rxru with 15 turns and an area of $0.40 \; m^{2}$ 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 and afg(pdl*upwvu6.o 7 y*rea $0.20 \; m^{2}$ 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 z(hm b/7gx/ z1sq wo; )yqafg2span of 60 m flies horizontally at a location where the downward component of the Earth's magnetic f /1; o (qa2zqbwmfz7syxgg/)hield is $6.0 \times 10^{-5} \; T$. 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 2.0dr)b40 s9 9o8zgjt phg m long rotates at a constant angular velocity of 2.0 rad/s about a vertical axis through o0ph 9o489t) dgzbrsgjne of its ends while in a constant magnetic field of $5.0 \times 10^{-5} \; T$. 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 loo)rsxg1vi1q,j;- n q 1 jex ph46kjuz .2nqdmu/ps and a cross-sectional area 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 consists of6aqng8x(y1q1q, q9 8os qt9x/nfsmgm 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 rectane64o5o)hy7irh qgyhoa y o929 gular loops on its armature. Each loop is 12 cm long and 8 cm wide. The armature rotates at 1200 rpm about an axis parallel to the long side. If the loop rotates in a uniform magnetic field of 0.30 T, which is perpendicular to the axis of rohy oq6)o5ey4 ooh2hai 7ygr99 tation, 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 of ares / ;i w57wtqkym0oy6ea $0.090 \; m^{2}$ 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 simpleuz 8kveh 5r)tg6co518z 57lecqm1fbnthg7( n AC generator with an output of 12 V maximum when rotattf (vh clc)17t5zr qmh uo15g8n 6bn 5egz7ke8ed at 60 Hz. A magnetic field of 0.050 T 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 withs9+ +t um cra*+k;plngqvw6gf,ca /q1 a maximum $emf$ 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 operates hh-buk- nch191cyu1i 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 bvqzb sx:b* ;7motor have a resistance of 6.00 W. The motor operates on 120 V AC, and whes* :v;bqbx7zbn 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 sg)z8e8 jl:5o p(r htrcupply. The operating current i erh):5c gol(z8t8p rjs 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 668 8de)dwc )extj mc-o.0 W is connected to a 24-V power supply. The operating current is 1.0 A at full speedw do -8c6m8ee)dx tc)j. What is the 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 resistance 6.0 W is 3 y ljk)6wwh m ,afp2yg/.zpdy9r5.a gconnected to a 24-V power supply. The operating current is 1.0 A at full sprg5 wd3j./ha2ywy a,f.9 my6pgpk) zleed. 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 to reduce a primarzn7ne 9:mli9 oy 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 2k sbh5ow0ay- primary of a transformer causes 14 A to flow in the secondary. How many turns are in the sec2 wo-0ba ykh5sondary?

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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 the1hjws 884f2akdgv hi6 24-V seco46s g hhaw88v1j fdi2kndary 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 p,orfc:7nfj /n3vfp*l rimary coil and a 2000-turn secondary coil. If the current in nlr f*/jp3 focf: nv,7the secondary 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 1i mqdy2ik*bcm 0c h75the primary of a transformer. Assuming 100% efficiency, how manyi02 mc5dqi ybk*hm71c amps at 24 V can flow in the secondary?

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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 transformer provides 7500 V at 10.0 lru0*des 1fm;t d3j* cmA. The primary coil operates on 120 V. Whatc0l det * um*1f3;rsdj does the 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 its primary coil and 300 tux*e ybgr 8rg,+rns on its secondary coil. If 120 V at 2.0 A is applied tr rb+y8g ,*xgeo 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 transformer has 60 turns on its primary *oy +jzr cky*d:t4pr.coil and 300 turns on its secondary coil. If 120 V at 2.0 A is applied to the primary, whatock4jrp:y*t+d* .zry current is present 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 turns and its od -0w 3pu+d:m tef.ensecondary has 200 turns. If the input current ao+dwfn-e 3 tudme. p0:t the primary is 100 A, we can expect the output current 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 100 turns and its secondary (pqswhc /2v;whas 200 turns. If the input voltv/;w sc2hp( wqage 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 100 turns and its s1)*s0,od mx3z1zbvhv2lb pwoecondary has 200 turns. If the p*, ws 1bpz2)b oxov10lzdvhm3 ower input to the primary is 100 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. Ty6d9,5hz0cyb 8 n iqpbhe voltage is usually stepped up to 4500 V by a transformer and transmitted through a8yi,0 9h6by5znpb cdq power line of total resistance 1.0 W. Find the number of turns in the secondary if the primary 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 sl xm750vmvr23y ic6hvoltage is usually stepped up to 4500 V by a transformer and transmitted through a power line of total resistance 1.0 mvlx vs07 r6y35hm 2icW. 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 V. Tw 2u/q, tpysg) t)lxh-he 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 transmisst q-t)g,ypl h2su )/xwion line 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 has a total resistance of 0.60 W. A gebz hb3vg, uu22fm5tx6nerator producevhfuux2bt g 62z,bm53s 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 transformer 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 0.60 W. A gek j:;.)*j uwedxo 0fns8 thqf3nerator produces 100 V at 70 A. In ordeqos;n d).fj8ek3x:wh *j0tfu r to reduce 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 would be yszk-gq9jh .)obkj-4m2 p7ug lo9j p7)- hjgskuo qbm2ky-.4 gzst 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 to be transmitted on a line wnq ed8.ro -sjthhf 0+6cq 58cot6iu*t+zk,l kith resistance of 0.60 W. To what voltage must the generator o s8 r+ko6,dtoitjh.qfn- qt 6c+u0c *e5kzlh8utput be stepped up with a transformer if the power 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 in th5qr1b:iz; whg,*rj tfn 1ul;b e coil's magnetic u:rl bw11;rb ngt5i* fqh;z,jfield?

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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 6.0gq f ezacanrgs :v;(5921lq 1gbtu 1/z-W resistor and an 18-H inductor. What is this circuit's time cona qbugc1v/e 91q;t gaz lfgr51(n2 sz:stant?

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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 voltageg72ezh,: jfvwu yj v8; in an AC circuit where the 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 placeda+w,cqyg eo0 d,)(r hj into 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 120-V AC ob0xj4 ;4ukut7e r ,u/kiv-l ffutlet. What is the resistance of the lamp,i ; jrvukftlu eu7b-0f4 x4/k?

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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 connected to a 120-V ac power supply. What is the peak /srsa3cvlf6mb. .hz:j;7 )md1 q uamzcurrent throu:m;aafhcb76 1d.u/)zm lsq. r3 mzjsvgh the resistor?

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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 power supply5u :.xqh.a2 xx -x n4dy2cxxrc. What is the power dissipated in thex q:.cur5 xc-a .x dhxnx2yx42 resistor?

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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-Wt/ ampp.kjz1,n nh:0z resistor is $I = 0.80 \sin (240 t)$. 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 a 50+st f(wscvzahtixj;a-ke dr77*11 +j -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 resistorcxf -2.kruj lj 3v/c8h 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 a 1.0-mH inductob3an-,w8h9a u yhdva+r 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 3dj,2ri :duxo of a 2.50-mH coil at 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 willx. z- okppqc(4 a 14.0-mH coil have 14.0 W of 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 inductive react* uy +cl ij;j/)mojmv9(l8ogmance 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 i,pits)smdas;n. uh3 1 .at r9x/( gvqqnductor when 120 V AC at a frequency of 20 kHz is applied to it?.,asudq h3 qar(sgs 1impv)t t.;x /n9

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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-mH coil due to a 110-V, 60p/b*utyf2p:; xw k 4/m4ecvpy.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 capl ahjgpph,1yhzt ,6nnij;6 :1acitor at 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 needed to have 50 W of capacitive reactance aubb,l8f,a b;b t 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 capacitor have a reactance of 1200cncxmfl*8z6 ;3roq z( 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 reactanceu;c60sy,l wzim :n(l l of a 0.010-mF capacitor be 100 W(z :y,mn0 cw 6;lluils?

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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 5.0 un y94x;mzz,d ,y qxv6V?

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115#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the impedancoa: d6n. h7wd8wg3mr ue of an ac series circuit with 12.0 W resistance, 15.0 W inductive reactance, and 10.0 W capacitive re:78uhwr a md3d .gwn6oactance?

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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 reszfnb 5t89h7hpu pgz8nj( qd,*istor, 20-mH coil, and 1.0-mF capacitor are cdpzn *9n(p hu gz,j788t5bhfq onnected 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 wp *qkt:-ob;p1500 Hz if a 100-W resistor, 20-mH coil, and 1.0-mF capacito pw;k:tp b*q-or are connected in 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 connected w/q du+kb0.x(w laxj +in series with a 20-mH inductor, what is the impedance at 1000 Hl/xa +u.dkb (qw+x 0jwz?

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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 connected in serie3j))s pwkpqa. s with a 20-mH inductor, what is the pwjq.skpp)) a3hase angle 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 needed izr x ./fh()fipoq)z0un a series circuit with a 20-mH coil and 1.0-mF capacitor for a total impedance of 100 W at 150xf)0f /ruo)z(qp .h iz0 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 in series with a 1o kd2 5urcr9j/ykclp33 1el4u 00-W resistor and 15-mH coil to get a total impe re1y9k/ ok3cjluu5l3p 42rcddance of 110 W at 2000 Hz?

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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 with a 450-mH inductor at 5000 Hx 4laa7;)te vym8xu v8caz.n4 z for a total impedancev84 xmcv.48)nazy eat ;xa7ul of 40000 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 100-kW resiv5,+n.(il k i0bg xwyxstor at 1.0-MHz for a to(lxvg+.kn w,ix0 yb i5tal impedance of 150 kW?

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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 i8agmbcik 5,k )n series with a 20-mF capacitor. What is the impedang8 )ima5kbc,kce 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 series with a 10-mF oy.re ) /txy1kcapacitor at 1.0 kHz for a total impedance oyky /)x.o 1retf 45 W?

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126#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What resistance is needed in seq + rahme b2kqc72 gy 7m;g;(tg.l6gxgries with a 10-mF capacitor at 1.0 kHz for a phase an;;myx7+( t e acmkghg rb2.7q q6ggl2ggle 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 a 30-W resistor at 1.0 kHz for a tota j-. n;np ag/g1tbas2yl impya bpg2;/s n.at- j1ngedance 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 capacitor b7v/-czn1ywi,n j 2vt at 120 Hz. What is the phase angleviv17yctn2nb -j,/wz?

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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-mH coil:hjp ru )o p94pp1zgu6, and 1.0-mF capacitor are connected in series?z:p 9uhpo14r pgp6 )uj

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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 10.7/eh8w .m zb)whixwf 30-mF capacitor, and a 0.350-H inductor. The circuit is connected to a 120-V, e8m .wxfwhb wzi/h )7360-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 capacitis qz :q26px ho2.u2lxave reactance 30 W, and an inductor of inductive reactance 30 W areo2: asqxul 2zqh2 x.p6 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 fo3xohqa c fed6i5 eh*e94:eatj fg23)dr a series RLC circuit containing a 50-W resistor, a 10-mF capahe )*hagof5df2 ie a343dtx qe9:jce6citor, and a 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-Wdhoh0 2 wz o:.28pxrbj resistor for a phase angle ofz8.h o0 hdj p2wob2rx: $40^{\circ}$ 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 mF. At what frequencu z a/ j04uqsjau:hg2mq q cau5s*:p9:y should the circuit be driven in order to have maz2 :jq/sag u :u*uq0: sa94quchmp a5jximum 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 ou8ry ovjy 14+ 8pk:um.(yjmspytput in an ac series circuit with 12.0 W resistance, 15.0 W inductive reactance, and 10.0 W capacitive reactance, when the circuit is conne1pj8yvp m ks.yrjo: 8y+4 um(ycted 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 cirxa7hy(ss u7h5 cuit 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 duy:m8dy3 4;-qbk e4ql)m hlsan impedance of 60 W and a resistance of 30 W. What is the power factor;:ydq umh)el -8 44smb 3kqydl?

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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 5yfmy/r)-mje if 3)k wy c2sw550-W resistor, a 10-mF capacitor, and a 0.45-H inductor, when connected to a 60-Hz power supf fm w3wcyyse-)m)ki/5 5rjy2ply?

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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 frequ gwr7x;l;ib*3qxlde0u hu* , hency of a 1.0-mF capacitor and a 15-mH coil in series? *eb* qxirgulw,hx0;l 3uhd7;

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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 series with a 4.7-wv22vjwoy,w 0/( ejrz mF capacitor for a resonant frequency of 10 kHz?j z2o0wjvw(/very,w2

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141#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What capacitance is 7gsluqu)n6oej5* *a yz y0 .ocneeded in series with a 3.7-mH inductor for a resonant frequency of 1000y7n05*)6zgu oucjaql* oe .ys 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 must be place 5bwox: /m8lwxd in series with a 30-W resistor and a 40-mH coil if the resonant frequency of the circbxm w5 xw/ol:8uit is to be 1000 Hz?

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