网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
单选题
An accidental path of low resistance, allowing passage of abnormal amount of current is known as a/an（）.
A
open circuit
B
short circuit
C
polarized ground
D
ground reference point
参考答案
参考解析
解析：
暂无解析
更多 “单选题An accidental path of low resistance, allowing passage of abnormal amount of current is known as a/an（）.A open circuitB short circuitC polarized groundD ground reference point” 相关考题
考题
109 Problems can occur in properly defining a project because:A. Project goals may not be agreeable to all partiesB. The plan was "too loose," thus allowing priorities to changeC. Low turnover of project personnelD. Too much communication between the client and project personnelE. The project objectives were quantified
考题
● Problems can occur in properly defining a project because:A Project goals may not be agreeable to all partiesB The plan was "too loose," thus allowing priorities to changeC Low turnover of project personnelD Too much communication between the client and project personnelE The project objectives were quantified
考题
According to the passage, which of the following about the borrower's financial weakness is false?A．Past record of repayment.B．Low profitability.C．Poor management.D．Heavy obligations to creditors.
考题
材料：The field current supply in older machines comes from a lower voltage direct current generator or exciter on the same shaft as the alternator. Modern machines however are either statically excited or of the high-speed brush-less type. The exciter is required to operate to counter the effects of power factor for a given load. The power factor is a measure of the phase difference between voltage and current and is expressed as the cosine of the phase angle. With a purely resistance load the voltage and the current are in phase, giving a power factor of one. The power consumed is therefore the product of voltage and current. Inductive or capacitive loads, combined with resistance loads, produce lagging or leading power factors which have a value less than one.The power consumed is therefore the product of current, voltage and power factor. The alternating current generator supplying a load has a voltage drop resulting from the load. When the load has a lagging power factor this voltage drop is considerable. Therefore the exciter, in maintaining the alternator voltage, must vary with load current and also the power factor. The speed change of the prime mover must also be taken into account.问题： The word “machines” in the passage refers to _____.A.the direct current generatorB.the alternating current generatorC.the exciterD.the prime moverWhich of the following statements is true according to the passage ?A.With a purely resistance load, the power factor is zeroB.Inductive loads combined with resistance loads produces leading power factorsC.Capacitive loads combined with resistance loads produces lagging power factorsD.With a purely resistance load, the phase angle is zeroWhen the load has a lagging power factor this voltage drop is considerable. This sentence means that _____.A.with a purely resistance load, the voltage drops too muchB.there is a considerable voltage drop in the capacitive load combined with resistance loadC.when the load is the capacitive load combined with resistance load, the voltage drops to zeroD.when the load is the inductive load combined with resistance load, the voltage drop is fairly largeThe exciter must vary with: ① load current ② the power factor, ③ speed change of the prime mover.A.①B.②C.①②D.①②③请帮忙给出每个问题的正确答案和分析，谢谢！
考题
______is a rounded projection at the forward end of a ship which reduces water resistance，thus allowing an increase in speed when the ships is in ballast．A.Bulbous bowB.Ellipse bowC.Cyclical projectionD.Gnomonic projection
考题
共用题干
第二篇Superconducting Ceramic（陶瓷）An underaround revolution beqins this winter. With the flip（轻击）of a switch, 30,000 homes in one part of Detroit will soon become the first in the country to receive electricity transmitted by ice-cold high-performance cables.Other American cities are expected to follow Detroit's example in the years ahead,which could conserve enormousamounts of rower.The new electrical cables at the Frisbie power station in Detroit are revolutionary because they are made of superconductors.A superconductor is a material that transmits electricity with little or no resistance.Resistance is the degree to which a substance resists electric current.All common electrical conductors have a certain amount of electrical resistance.They convert at least some of the electrical energy passing through them into waste heat.Superconductors don't.No one understands how superconductivity works.It just does.Making superconductors isn't easy.A superconducting material has to be cooled to an extremely low temperature to lose its resistance.The first superconductors,made more than 50 years ago,had to be cooled to -263 degrees Celsius before they lost their resistance.Newer superconducting materials lose their resistance at-143 degrees Celsius.The superconductors cable installed at the Frisbie station is made of a ceramic material that contains copper,oxygen,bismuth（秘）,strontium（锶）and calcium (钙）.A ceramic is a hard,strong compound made from clay or minerals.The superconducting ceramic has been fashioned into a tape that is wrapped lengthwise around a long tube filled with liquid nitrogen.Liquid nitrogen is supercold and lowers the temperature of the ceramic tape to the point where it conveys electricity with zero resistance.The United States loses an enormous amount of electricity each year to resistance. Because cooled superconductors have no resistance,they waste much less power. Other cities are watching the Frisbie experiment in the hope that they might switch to superconducting cable and conserve power,too.According tothe last paragraph,which of the following statements is NOT true?A:Other cities hope they can also conserve power.B:Other cities hope they can use superconducting cables soon.C:Superconductors waste less power because of their low resistance.D:The Frisbie experiment is not successful.
考题
Which two statements are true about Voice over IP （VoIP） packet delivery in a digital infrastructure？ （）A、 Packets can arrive out of order.B、 Packets must take the same path to the destination.C、 Once packets are received at the destination router， the router performs sampling to ensure the quality of the voice traffic.D、 Packets can experience varying delays across the network.E、 Packets containing voice samples are sequentially numbered by default， allowing for reordering upon arrival at the terminal router along the path.
考题
（ ）is not the advantage of GERT （Graphical evaluation and review techniques）as compared with PERT （project evaluation and review techniques）. A、Allowing loopingB、Allowing for dummy tasksC、Allowing branchingD、Allowing multiple project end results
考题
According to Ohm’s Law， which of the following is correct？（）A、As voltage increases， resistance decreasesB、As amperage decreases， resistance decreasesC、As resistance decreases， amperage increasesD、As resistance increases， voltage increases
考题
以下选项中哪个是以作者模式打开已经存在的MMC（）。A、MMC path/filename.msc/aB、path/filename.msc/aC、MMC path/filename.mscD、path/filename.msc
考题
单选题According to the passage, Dr. Barry was made fun of because she______.A
had a low voiceB
had a funny beardC
was tallD
was short
考题
单选题Some large A-Cmotors are equipped with heatersThese could be （） (1)resistance heaters bolted directly to the frame (2)low voltage windings embedded in the motor windingsA
(1) onlyB
(2) onlyC
either (1) or (2)D
neither (1) or (2)
考题
单选题The most suitable title for the passage might be _____.A
Funny Computer UsersB
High-tech and Low-techC
Computers and Helpline UsersD
A Qualified Computer User
考题
单选题If a voltmeter is connected across a line, it must be protected with a（）A
shuntB
high-resistance coil in the armature circuitC
low-resistance coil in the armature circuitD
shunt and a coil of high resistance
考题
单选题In the passage, the author implies that _____.A
it is not good for people to travel aloneB
one should explore philosophical problems under the guidance of other philosophersC
one should follow the path of other philosophersD
one would study philosophy with others
考题
单选题According to the passage, Mediterranean diet______.A
can’t control the blood sugar unless combined with exercise.B
is better than the low-fat diet in treating diabetes.C
involves more carbohydrates than the low-fat diet.D
can completely replace diabetes drugs.
考题
单选题Monsoons are characterized by （）.A
light，variable winds with little or no humidityB
strong，gusty winds that blow from the same general direction all yearC
steady winds that reverse direction semiannuallyD
strong，cyclonic winds that change direction to conform to the passage of an extreme low pressure system
考题
单选题According to Ohm’s Law， which of the following is correct？（）A
As voltage increases， resistance decreasesB
As amperage decreases， resistance decreasesC
As resistance decreases， amperage increasesD
As resistance increases， voltage increases
考题
单选题From the passage we can learn that MDC Company always ______.A
keeps its promiseB
provides the same productsC
sells its products at a low priceD
delivers its products without delay
考题
单选题Copper is often used as an electrical conductor because it （）.A
has high resistance at low temperaturesB
has a highly polished surfaceC
is able to pass current with little oppositionD
holds insulation together well
考题
单选题Most conducting materials such as copper, aluminum, iron, nickel, and tungsten （）.A
increase in resistance with increased temperatureB
increase in resistance with decreased temperatureC
decrease in resistance with increased temperatureD
increase in conductance with increased temperature
考题
单选题According to the passage, Mediterranean diet _____.A
can’t control the blood sugar unless combined with exercise.B
is better than the low-fat diet in treating diabetes.C
involves more carbohydrates than the low-fat diet.D
can completely replace diabetes drugs.
考题
单选题The most suitable title for the passage might be______.A
Funny Computer Users.B
High-tech and Low-tech.C
Computers and Helpline Users.D
A Qualified Computer User.
热门标签
最新试卷