相关试题
【单选题】
两个电容量相同的电容器，串联的等效电容量和并联的等效电容量之比为___。
A. 4/1
B. 2/1
C. 1/2
D. 1/4
【单选题】
电压表的内阻为3kΩ，最大量程为3V，现将它串联一个电阻，改装成量程为15V的电压表，则串联电阻值为___。
A. 3kΩ
B. 9kΩ
C. 12kΩ
D. 16kΩ
【单选题】
任一瞬间电感上的电压与自感电势大小___。
A. 相等，方向相同
B. 不等，方向相反
C. 相等，方向相反
D. 不等，方向相同
【单选题】
三相交流电源的星形连接，线电压和相电压之间的关系是___。
A. Uab=1.732Ua
B. Uab=Ua
C. Uab3Ua
D. Uab=2Ua
【单选题】
三相电源做三角形连接时，线电压Ux与相电压Ua之间的关系是___。
A. Ux=Ua
B. Ux=1.732Ua
C. Ux=3Ua
D. Ux=2Ua
【单选题】
从负荷曲线上可直接反映出日用电量、日最大负荷、日平均负荷和___。
A. 无功功率
B. 有功功率
C. 日负荷率
D. 日用电量
【单选题】
电磁式继电器是根据___原理工作的。
A. 电磁感应
B. 磁感应
C. 极化
D. 电磁现象
【单选题】
___不属于基本远动系统构成部分。
A. 通信信道
B. 变压器
C. RTU
D. 调度端
【单选题】
在交流电路中，纯电容的容抗与电感的电抗方向___。
A. 相反
B. 同相
C. 无关系
D. 不确定
【判断题】
力沿其作用线移动后，对刚体上某一点的力矩保持不变。
【判断题】
构件的内力是由外力作用而引起的，其大小将随外力的变化而变化。
【判断题】
在作用着已知力系的刚体上，加入一个平衡力系后，一定会改变刚体的原状态。
【判断题】
电连接的作用是保证接触网各导线间或各分段间、各股道悬挂以及承力索和接触线之间电流的畅通。
【判断题】
约束反力的方向总是与被限制物体的运动方向相同。
【判断题】
光滑约束反力的方向是沿着接触面的公法线，而背离物体。
【判断题】
用多边形法则求平面汇交力系的合力时，可以改变各分力的相加顺序，同时也可以改变个分力的大小和方向。
【判断题】
在闭合回路中，列回路方程时，其回路方向可以任意假设。
【判断题】
叠加原理适用于线性电路中某一支路的电压、电流、功率计算。
【判断题】
只要线圈中穿过的磁通量大，则感应电势一定大。
【判断题】
通过电阻上的电流增大到原来的2倍时，它所消耗的电功率也增大到原来的2倍。
【判断题】
几个电阻并联时，总电阻一定小于各并联的电阻值。
【判断题】
电分相两侧电压差较大时，电压亦可同相。
【判断题】
软横跨直吊线用两股φ4.0mm铁线拧成，上端应做临时性固定，下端做成永久性固定。
【判断题】
双横向承力索应使两根张力相等，V形联板不应偏斜；上、下部固定绳承载后允许微向上弯曲。
【判断题】
补偿坠砣挂在导线末端进行张力调整，使导线设定的张力在气温变化时基本保持衡定。
【判断题】
软横跨由横向承力索和上、下部固定绳组成。
【判断题】
供电线对地电压一般按27.5kV考虑。
【判断题】
自耦变压器供电方式简称“AT”供电方式。
【判断题】
回流线是作用是将轨道回路内的牵引电流吸回牵引变电所。
【判断题】
回流线是钢轨回路与牵引变电所之间的连接线。
【判断题】
馈电线是牵引变电所与接触网之间的连接线。
推荐试题
【单选题】
He wrote an article criticizing the Greek poet and won ___and a scholarship.
A. faith
B. prestige
C. status
D. courage
【单选题】
Jane was hit on the head by the robber and was knocked___.
A. mindless
B. unaware
C. brainless
D. unconscious
【单选题】
It is our___policy that we will achieve unity through peaceful means.
A. consistent
B. continuous
C. considerate
D. continual
【单选题】
The author of the report is well___with the problems in the hospital because he has been working there for many years.
A. informed
B. acquainted
C. enlightened
D. acknowledged
【单选题】
The manager lost his ___ just because his secretary was ten minutes late.
A. mood
B. temper
C. mind
D. passion
【单选题】
Many Europeans___ the continent of Africa in the 19th century.
A. exploded
B. explored
C. exposed
D. expanded
【单选题】
If you hear such a rumor,___ it thoroughly.
A. seek
B. investigate
C. search
D. explore
【单选题】
The pressure ___causes Americans to be energetic, but it also puts them under a constant emotional strain.
A. to compete
B. competing
C. to be competed
D. having competed
【单选题】
Having decided to rent a flat, we ___ contacting all the accommodation agencies in the city.
A. set about
B. set on
C. set out
D. set up
【单选题】
The old couple decided to ___ a boy and a girl though they had three children of their own.
A. adapt
B. adjust
C. adept
D. adopt
【单选题】
Mike was being ___for violent tendencies.
A. contended
B. consulted
C. counselled
D. insulted
【单选题】
I will___ Mr. Walters on this point.
A. refer to
B. commit to
C. contribute to
D. defer to
【单选题】
What happens in the next few days is___to our success.
A. critical
B. critic
C. prior
D. valid
【单选题】
She won’t___that there is a problem.
A. confer
B. concern
C. acknowledge
D. contemplate
【单选题】
This offer is___ for travel before the end of April.
A. effective
B. ineffective
C. invalid
D. valid
【单选题】
___ to British universities depends on examination results.
A. Admittance
B. Entry
C. Admission
D.
E. ntrance
【单选题】
The database is only ___ by authorized managers.
A. proved
B. accessible
C. approved
D. access
【单选题】
This traditional ___ is of indigo blue.
A. clothes
B. diversity
C. costume
D. institution
【单选题】
These cigarettes are a ___ of the best tobaccos.
A. blend
B. band
C. mixture
D. mess
【单选题】
The tennis players need total ___ during play.
A. concentration
B. section
C. depression
D. energy
【单选题】
He ___ that he was innocent.
A. announced
B. declared
C. disclosed
D. admitted
【单选题】
Columbus discovered America but did not ___ the new continent.
A. seek
B. investigate
C. search
D. explore
【单选题】
The trees ___their foliage every year.
A. repeat
B. grow
C. refresh
D. renew
【单选题】
Make a list of the various ___.
A. options
B. choice
C. optional
D. samples
【单选题】
I am well aware that this is a ___ job.
A. rough
B. tough
C. wealthy
D. rogue
【单选题】
I found their kindness quite ___.
A. strong
B. overweening
C. keen
D. overwhelming
【单选题】
The captain wasn’t ___ on having him in the team.
A. eager
B. keen
C. overwhelmed
D. anxious
【单选题】
He was ___at the prospect of seeing them again.
A. thrilling
B. blessed
C. thrilled
D. emotional
【单选题】
They ___ against travelling at night in such a dangerous country.
A. consul
B. advocate
C. counsel
D. recommend
【单选题】
It is absolutely vital that food supplied should be ___.
A. sustained
B. enhanced
C. exhausted
D. maintained
【单选题】
He must have had an accident, or he ___ then.
A. would have been here
B. had to be here
C. should be here
D. would be here
【单选题】
It was essential that the application forms ___ back before the deadline (截止日期).
A. must be sent
B. would be sent
C. be sent
D. were sent
【单选题】
We ___ our breakfast when an old man came to the door.
A. just have had
B. have just had
C. just had
D. had just had
【单选题】
The bridge was named ___ the hero who gave his life for the cause of the people.
A. after
B. with
C. by
D. from
【单选题】
It wasn’t such a good dinner ___ she had promised us.
A. that
B. which
C. as
D. what
【单选题】
The road now ___two kilometers beyond the river.
A. develops
B. extends
C. expands
D. widens
【单选题】
It was claimed that the level of alcohol in the man’s blood was ___ to cause an accident.
A. sufficient
B. adequate
C. enough
D. accurate
【单选题】
Medical care reform has become this country’s most important public health ___.
A. question
B. stuff
C. matter
D. problem
【单选题】
His retail business in the city___ rapidly between the wars.
A. enlarged
B. extended
C. widened
D. expanded
【单选题】
Many frogs ___ the sound of their voice using special sacs(囊) in their throat.
A. amplify
B. widen
C. expand
D. enlarge
