51fly国际课程 (51fly.win)

 找回密码
 立即注册

手机扫一扫，访问本页面

 

      

上传图片附件

未使用图片

小贴士: 允许的图片文件格式为: gif, jpg, jpeg, png, webp，上传完成后会在上方生成预览，用鼠标连续双击缩略图，或拖动缩略图，该图片就被绑定至本题，显示在题目下方

本次作答已使用

小贴士: 此栏目显示的是当前作答使用的所有图片，绑定到某一题目的图片同时会显示在该题目下方; 删除使用的图片会将其转移到<未使用图片>类别


习题练习：Physics Unit18: Electric Currents
本习题练习试卷来源于51fly国际课程 (https://51fly.win)， 为试卷打印版，您也可以在网站平台(https://autodiscover.51fly.win/)直接 访问本试卷的在线电子版并查看正确答案与解析，搜藏保存任意题目到收藏集。 访问方法: 平台首页左上角"通过试卷号快速访问"输入试卷号 76，并点击直达试卷；或浏览器地址栏内直接输入本试卷链接 https://autodiscover.51fly.win/test76.html  教师使用本平台可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力。
 作者: physics  发布日期: 2022-08-17 11:19    总分: 80分  得分: _____________

答题人: 游客未登录  开始时间: 22年08月17日 11:19  切换到: 整卷模式

标记此题
1#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A device that produces electri,m*hs/kmpo ,o city by transforming chemical energy into electrical energy is called ,okmsh p,mo* /a

参考答案:    
标记此题
2#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A car battery

参考答案:    
标记此题
3#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The total amount of charge that passes through a wireq7z ak 6-u1k ;oswgp2e's full cross section at any point per a ekpo;kws2q6 zu17- gunit of time is referred to as

参考答案:    
标记此题
4#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The direction of convention current is taken to be the directioo4n.2ywcib-i,i t r m:n that

参考答案:    
标记此题
5#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A coulomb per second is th qa qs5lx/fo1jpm1u(cntd3;m ,c9 g f-e same as

参考答案:    
标记此题
6#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Car batteries are rated in "amp-hours." Tvrbh )xwdt8 hbo h2*b4y11r3mei b 7w6u*ee2 ohis is a measure of their

参考答案:    
标记此题
7#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The resistance of a wire is defined a l5sq .ki/eluuf :/*dleus+2ts

参考答案:    
标记此题
8#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is $1 \; \Omega$ equivalent to?

参考答案:    
标记此题
9#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The resistance of a wi p2owsrt:e q5-re is

参考答案:    
标记此题
10#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The resistivity of a wlehtu7- fr,q :a 0,mepire depends on

参考答案:    
标记此题
11#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Which conducting material has the lowest resistivity vi4/x) k h)jad-bzztjrbx4 9m+alue?

参考答案:    
标记此题
12#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider two copper wires. One hapaor x j v-)c (ge,7ywquf9uj*r,/g;bs twice the length of the other. How do the resistivities ofjcjub(/prg wy;u e*ox7qr- af)g, v,9 these two wires compare?

参考答案:    
标记此题
13#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider two copper wires. One has twice thywkz j; l ,xf+gqy3;k1gx, ;-tw u4sgje length of the other. How do the resistances of th ku,fkg4 ;-;w3g t,jzx+yw j1ly;qxg sese two wires compare?

参考答案:    
标记此题
14#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider two copper wmq )ii7 ,uppx+b jo3*mt5v7u:g6tika ires. One has twice the cross-sectional area of the other. How d+xu p ub p i67qgi:k3o,tm7ima)*jt v5o the resistances of these two wires compare?

参考答案:    
标记此题
15#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider two copper wires. One has twice the length and twice the cross-sg1 . cifjt *+ tn:n6pu5e-bigcectional area of the other. How do the resistances of these j5 -ubngin :c.6*c gft+itpe1two wires compare?

参考答案:    
标记此题
16#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The length of a wire is doubled and them ya0yk/06o. ywmlvb 6yhk( 3p radius is doubled. By what factor does the resistance change?myb.6ma/ kow603(lpkyyhv y0

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
17#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How much more resistance does a; l8drqn*zo;bqk35q w 1.0 cm diameter rod have compared to a 2.0 cm diameter rod of the same length and made of the qd3;w* nz8q 5qr;lobksame material?

参考答案:    
标记此题
18#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The resistivity of mosto 6 olhqu;i3t( common metals

参考答案:    
标记此题
19#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Negative temperature coefficients; gmdow ca hsbluvhw309,/)j. of resistivity

参考答案:    
标记此题
20#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is 1 W equivalent 6l ub3ah.+)jk6egzdhto?

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
21#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A kilowatt-hour is equivalent to-vp:av) m1-9ydajip s 4 xks*v

参考答案:    
标记此题
22#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If the resistance in a constant voltage circuit 3(5z xcfvq 0hyssr2l7ow s29qis doubled, the power dissipated by thatq9rq x5y(z2 0vhl2o7ws sfc s3 circuit will

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
23#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If the voltage across a circuit of constant resistance is doubled, the 6l4,iobri :80 itxqiz power diss6l4x itzi80:,birqio ipated by that circuit will

参考答案:    
标记此题
24#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If the resistance in a circuiej f8dsuscu*nr4n(fn .,+uj* t with constant current flowing is doubled, the power dissipated by that cd( fnjsjf *s*r8. +u4cn,euunircuit will

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
25#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If the current flowing through a circuit of constant resish a x9td6qgy-efjjiq1 (1a.q v4vjv5, tance is doubled, the power dissipated by that circuiijx1j.vv f( a 64tqa 1,yqqeh-g9vdj5t will

参考答案:    
标记此题
26#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  During a power demand, the volta+zks 0.( fvighu,n h/j;ki1 trge output is reduced by 5.0%. By what percentage is the power on a resistor affectn .1z hi(if;v+rtgjs kh,uk/0ed?

参考答案:    
标记此题
27#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A current that is sinusoidal with respect to tqcdtjh0o8 +/ctq: l9sime is referred to as

参考答案:    
标记此题
28#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Consider two copper wires each carrying a current of 3.0 A. One wire has twicem8 omu+8i4sx (rg (+p6ivr0feoqoa6 gzu 7 bq2 the diameter of the other. The ratio of the drift velocity in the smaller diameter wire to that in iq x( 7o e+iqap8uf+ozogg6us2(v bmmr6r804the larger diameter wire is

参考答案:    
标记此题
29#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Materials in which the resistivqhz 6;wmh6 p,o,u2s poity becomes essentially zero at very low temperatures are 6;owmhuq2o6,, p zp hsreferred to as

参考答案:    
标记此题
30#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What current is flowing if 0.67 C of charge pass a pois qcqk5 tf ;b-f)0j 6.rtusl6mnt in 0.30 s?

参考答案:    
标记此题
31#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A charge of 12 C passes through an l gb/:91krcs-mjt/ qgelectroplating apparatus in 2.0 min. What is 9c-1 //ggstq mbl:kjrthe average current?

参考答案:    
标记此题
32#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How much charge must pass by a point in 10 s for -o/,sf q+a27pcyr1 nl qcd 1lwthe current to be 0.50 A?

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
33#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A total of $2.0 \times 10^{13} \; protons$ pass a given point in 15 s. What is the current?

参考答案:    
标记此题
34#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What current is flowin+3oldhdw*s-z(g* vai g if $4.0 \times 10^{16} \; electrons$ pass a point in 0.50 s?

参考答案:    
标记此题
35#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  If $3.0 \times 10^{15} \; electrons$ flow through a section of a wire of diameter 2.0 mm in 4.0 s, what is the current in the wire?

参考答案:    
标记此题
36#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A coffee maker, which draws 13.5 A of current,nw(,dy( lvr21,,,wes5p,jp u o wq ngu has been left on for 10 min. What is the net number of electrons that have vw qgs , 2e,jlypwp,,wn(rou5 u1nd(, passed through the coffee maker?

参考答案:    
标记此题
37#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  In an electroplating process, it is desi (f4de6 l oa4rp)ou/adred to deposit 40 mg of silver on a metal part by using a current of 2.0 A. How long must t ( f 4oa4a6u/ep)doldrhe current be allowed to run to deposit this much silver? (The silver ions are singly charged, and the atomic weight of silver is 108.)

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
38#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What potential difference is required to cause 4.00 A to flow through a resi*uxvkp /*v/ha stan kv/xa*puv h/*ce of 330 W?

参考答案:    
标记此题
39#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the voltage across a 5.0-W resistor i;r1ayg vab 3n/f the current through it is 5.0 A?

参考答案:    
标记此题
40#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 4000-W resistor is cond 3of hq0t8z /vu+rftc,fz0.lnected across 220 V. What current will flow?

参考答案:    
标记此题
41#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A light bulb operating at 110 V draws 1.40 A of current. What i )jepcswk: u/wx( **oks its resistance?(j/xk :ow c* upk*esw)

参考答案:    
标记此题
42#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 12-V battery is connected to a 100-W resisto ) smsbbeh+* dccv 4r53q9zmc2r. How many electrons flow through the wire i2msv) c d3z*e cs9+cmq4 rbbh5n
1.0 min?

参考答案:    
标记此题
43#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the resistance of 1.0 m nnufi/ //xqvw ix65 .qcopper wire of diameter 0.40 inch? (The resistivifnwqxnquv / .ix/6/5 ity of copper is $1.68 \times 10^{-8} \; \Omega \cdot m$.)

参考答案:    
标记此题
44#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the resistance of a ciomq+be*)l ki 0rcular rod 1.0 cm in diameter and 45 m long, if the resistivity isol b0i+) q*emk $1.4 \times 10^{-8} \; \Omega \cdot m$?

参考答案:    
标记此题
45#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What length of copper wire (-+pmn86pa o/ze 5t x1rl8 iwydresistivity $1.68 \times 10^{-8} \; \Omega \cdot m$) of diameter 0.15 mm is needed for a total resistance of $15 \; \Omega$?

参考答案:    
标记此题
46#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 120-m long copper b -)s k.b7grayagka 92wire (resistivity $1.68 \times 10^{-8} \; \Omega \cdot m$) has resistance $6.0 \; \Omega$. What is the diameter of the wire?

参考答案:    
标记此题
47#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 1.5-cm square rod, 4.0 m long, measures 0.040 ohms. What is its *9 33fkyyh* dxhjm.wlresistivity?

参考答案:    
标记此题
48#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  Calculate the current through a 10.0-m long 22 gauge (the radiu1u44j2qsvs3 )pcxzsfs is 0.321 mm) nichrome wire if it is connected to a 12c14v js 3uxz24sp)s qf.0-V battery. (The resistivity of nichrome is $100 \times 10^{-8} \; \Omega \cdot m$.)

参考答案:    
标记此题
49#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A heavy bus bar is 20 cm long and of rectangular cross-section, / 2dw rmd4wm7o )bsza(1.0 cm x 2.0 cm. What is the voltage drop along its length when it carri( 4d)b w/7sw dmazo2mres 4000 A? (The resistivity of copper is $1.68 \times 10^{-8} \Omega \cdot m$)

参考答案:    
标记此题
50#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 1.0-m length of nichrome ,2-wl trh6+cpw+xznz )3gt5tij1qmewire has a radius of 0.50 mm and a resistivity of $100 \times 10^{-8} \; \Omega \cdot m$. If the wire carries a current of 0.50 A, what is the voltage across the wire?

参考答案:    
标记此题
51#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 1.0-mm diameter copper wirtm8ot kry e/9 gt52z4ye (resistivity $1.68 \times 10^{-8} \; \Omega \cdot m$) carries a current of 15 A. What is the potential difference between two points 100 m apart?

参考答案:    
标记此题
52#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A carbon resistor has a i yi4lf0napp cstf8)q0w me 5u0f 02-uresistance of $18 \Omega$ at a temperature of $20 ^{\circ}C$. What is its resistance at a temperature of $120 ^{\circ}C$? (The temperature coefficient of resistivity for carbon is $-5.0 \times 10^{-4} /^{\circ}C$.)

参考答案:    
标记此题
53#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The temperature coefficient of resistivig1pcc 3v1bk4 0xs o7:y htvi;ity of platinum is $3.9 \times 10^{-3} /^{\circ}C$. If a platinum wire has a resistance of R at room temperature ($23 ^{\circ}C$), to what temperature must it be heated in order to double its resistance to 2R?

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
54#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A platinum wire is used to determine the melting point ri.daak34sz-jx2t:5yk h(paof indium. The resistance of the platid 3zpj. iskt(452:x-kara hya num wire is $2.000 \; \Omega$ at $20 ^{\circ}C$ and increases to $3.072 \; \Omega$ as indium starts to melt. What is the melting point of indium? (The temperature coefficient of resistivity for platinum is $3.9 \times 10^{-3} /^{\circ}C$.)

参考答案:    
标记此题
55#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  5.00 A is flowing through 4cae2lzb k:;kw d(xtf.:yy4 uan $10.0 \; \Omega$ resistor. How much power is being dissipated?

参考答案:    
标记此题
56#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 110-V hair dryer is rated at 1200 W. What currentcunbd o o6q* l65,esj3 will it draw?

参考答案:    
标记此题
57#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 150-W light bulb running on 1106gyv8yfo7,6 asr, c 8eodl8 ir V draws how much current?

参考答案:    
标记此题
58#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  What is the nominal resistance of a 100-W light bulb designed to b)zok3 d1h ekj+e used in a 120-V circuit?z)d j+ekh ok31

参考答案:    
标记此题
59#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A toaster is rated 800 W at 120 V. What is the resistancn* zefg79ay+ye of its heating element?*n9 gye7+zyaf

参考答案:    
标记此题
60#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 200-W resistor is rated at )4lmb 93imzsq$1/4 \; \Omega$. What is the maximum current it can draw?

参考答案:    
标记此题
61#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 200-W resistor is rajvypm)1*8o g eted at $1/4 \; \Omega$. What is the maximum voltage?

参考答案:    
标记此题
62#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A lamp uses a 150-W bulb. If it is ilzk0 (d zz h)*p0knz*used at 120 V, what current does it draw?

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
63#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A lamp uses a 150-W bulb. If it is used at 120 V, what is its resi*hi(kw k br4xur21*w e8osb;ostance?

参考答案:    
标记此题
64#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 25-W soldering iron runs on 11lt+z49mf4w n f cfndx, hs/6i10 V. What is its resistance?

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
65#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How much does it cost to operate a 25-W soldering iron for 8.0 29dkcce uc ;5yhours, if energy 9cce2uy ;cd 5kcosts $0.08/kWh?

参考答案:    
标记此题
66#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How much energy does a 100-W light bulb use in 5u8rpsz eo*+ c8.0 hours?

参考答案:    
标记此题
67#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 1500-W heater is connected to a 120-V line for 2.0 hours. How much heat 6db oeqv-c le (zd1z08energy is d0 vz1bd8o-c le(6ezq produced?

参考答案:    
标记此题
68#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A battery is rated at 12 V and 160vos z6 5/ap 7vr5sqoj/ A-h. How much energy does the battery store? o7 s6p5oajq/ zr5vvs/

参考答案:    
标记此题
69#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  How much energy does a g48jdjbi aeh dyny(1;kao/, :25-W soldering iron use in 8.0 hours?

参考答案:    
标记此题
70#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 100-W driveway light bulb is on 10 hoursw + kb1r;y:xvf per day. Assuming the power company charges 10 cents for each kilowatt-hour:vk+;b r1fwyx of electricity used, estimate the annual cost to operate the bulb.

参考答案:    
标记此题
71#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 400-W computer (computer plus monitor) is turned on c5gpe )wq 6bada ,eu.48.0 hours per day. If electricity co6,5qcbugea dap 4ew).sts 10 cents per kWh, how much does it cost to run the computer annually?

参考答案:    
标记此题
72#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The monthly (30 days) electricvv uc -b)q0s)y-tlf a+ bill included the cost of running a central air-conditioning unit for 2.0 hr/day-vfs)+ 0c qba-)y ltuv at 5000 W, and a series connection of ten 60 W light bulbs for 5.0 hr/day. How much did these items contribute to the cost of the monthly electric bill if electricity costs 8.0 cents per kWh?

参考答案:    
标记此题
73#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The heating element in an electric drier opera2 e3pt(s l6foq8gz ho3,m)xm sx2as/m7nbc8wtes on 240 V and generates heat at the rate of 2.1 kW. The heating element shorts out and, in repairing it, the owner shortens the Nichrome wire b,a()smwt3c 6 h827/lo8 zgno3ps2xfm se xbqm y 10%. (Assume the temperature is unchanged. In reality, the resistivity of the wire will depend on its temperature.) What effect will the repair have on the power dissipated in the heating element?

参考答案:    
标记此题
74#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  14 A of current flows thr6;6w:;- fnzupotrwzd dwu-j t3sn1 n (ough $8.0 \; \Omega$ resistor for 24 hours. How much does this cost if energy costs $0.09/kWh?

参考答案:    
标记此题
75#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 9.0-V battery costs xpm-ugc 32k*y $1.49, and will run a portable CD player for 6.0 hours. Suppose the battery supplies a current of 25 mA to the player. What is the cost of energy in dollars per kWh?

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
76#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A motor that can do work at the rate of 2.0 hp has 60% effici;pvwf dll z57+l iu/u*ency. How much current does it draw/udu7ivwzl l l +*;5pf from a 120-V line? ($1 \; hp = 746 \; W$)

参考答案:    
标记此题
77#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 500-W device is connected to a 120-V ac power source. What qk; t6fmez6:*apb ya/rms current flows tp qak6yz/:6tm abe ;f*hrough this device?

参考答案:    
标记此题
78#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 500-W device is connected to a 120-V ac power source. What peak current flob- )xiemz*/xlne:v e 5ws through this devi vix*xn b/5ee):z-eml ce?

参考答案:    
本习题练习题目来源于51fly国际课程 (https://51fly.win)，学生可刷题练习，扫右侧二维码或加微信xxxxxxxxxx，获取更多资料
教师可以抽题组卷或一键复制本试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力
标记此题
79#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  A 500-W device is connected to a 120-V ac p-+ kodzl rw9m+ower source. What is the peak voltage acr zwrl-+odm9 k+oss this device?

参考答案:    
标记此题
80#
 
单选题 ( 1.0 分) 切至整卷模式 搜藏此题  
  The diameter of a copper wire is 0.081 inch. Thev(blnquw,5w,q ygd,a7,or/0g qe 5u d maximum safe current it can carry (in order to prevent fire danger in building construction) is 20 A. At this current, what is the drift velocity of the electrons? (The number of elect qoq uuw, gv,qdb/,n, eg5(wly0rda 57ron carriers in one cubic centimeter of copper is $8.5 \times 10^{22}$.)

参考答案:    
  • 姓名:游客(未登录)
    •
    总分:80分 及格:48分 时间:不限时
    未答题: 已答题:0 答错题:
    当前第 题，此次习题练习共有 80 道题

    试卷内容到此结束!   © 2025 51fly国际课程 (https://51fly.win)版权所有

    浏览记录|手机版视频|手机版试卷|使用帮助|51fly国际课程 (https://51fly.win)

    GMT+8, 2025-12-20 01:57 , Processed in 1.201456 second(s), 190 queries , Redis On.