相关试题
【判断题】
用电笔验电时,应赤脚站立,保证与大地有良好的接触。
【判断题】
用钳表测量电动机空转电流时,不需要档位变换可直接进行测量。
【判断题】
用钳表测量电动机空转电流时,可直接用小电流档一次测量出来。
【判断题】
用钳表测量电流时,尽量将导线置于钳口铁芯中间,以减少测量误差。
【判断题】
用万用表R×1kΩ欧姆档测量二极管时,红表笔接一只脚,黑表笔接另一只脚测得的电阻值约为几百欧姆,反向测量时电阻值很大,则该二极管是好的。
【判断题】
用星-三角降压启动时,启动转矩为直接采用三角形联结时启动转矩的1/3。
【判断题】
右手定则是判定直导体做切割磁力线运动时所产生的感生电流方向。
【判断题】
幼儿园及小学等儿童活动场所插座安装高度不宜小于1.8m。
【判断题】
雨天气,即使在室内也不要修理家中的电气线路、开关、插座等。如果一定要修要把家中电源总开关拉开。
【判断题】
载流导体在磁场中一定受到磁场力的作用。
【判断题】
再生发电制动只用于电动机转速高于同步转速的场合。
【判断题】
在安全色标中用红色表示禁止、停止或消防。(
【判断题】
在安全色标中用绿色表示安全、通过、允许、工作。
【判断题】
在爆炸危险场所,应采用三相四线制,单相三线制方式供电。
【判断题】
在采用多级熔断器保护中,后级熔体的额定电流比前级大,以电源端为最前端。
【判断题】
在串联电路中,电路总电压等于各电阻的分电压之和。
【判断题】
在带电灭火时,如果用喷雾水枪应将水枪喷嘴接地,并穿上绝缘靴和戴上绝缘手套,才可进行灭火操作。
【判断题】
在电气线路安装时,导线与导线或导线与电气螺栓之间的连接最易引发火灾的连接工艺是()。
【判断题】
在电气原理图中,当触点图形垂直放置时,以“左开右闭”原则绘制。
【判断题】
在电压低于额定值的一定比例后能自动断电的称为欠压保护。
【判断题】
在断电之后,电动机停转,当电网再次来电,电动机能自行起动的运行方式称为失压保护。
【判断题】
在高压操作中,无遮拦作业人体或其所携带工具与带电体之间的距离应不少于0.7m。
【判断题】
在高压线路发生火灾时,应采用有相应绝缘等级的绝缘工具,迅速拉开隔离开关切断电源,选择二氧化碳或者干粉灭火器进行灭火。
【判断题】
在供配电系统和设备自动系统中,刀开关通常用于电源隔离。
【判断题】
在没有用验电器验电前,线路应视为有电。
【判断题】
在三相交流电路中,负载为星形接法时,其相电压等于三相电源的线电压。
【判断题】
在设备运行中,发生起火的原因是电流热量是间接原因,而火花或电弧则是直接原因。
【判断题】
在我国,超高压送电线路基本上是架空敷设。
【判断题】
在选择导线时必须考虑线路投资,但导线截面积不能太小。
【判断题】
在有爆炸和火灾危险的场所,应尽量少用或不用携带式、移动式的电气设备。
【判断题】
遮栏是为防止工作人员无意碰到带电设备部分而装设备的屏护,分临时遮栏和常设遮栏两种。
【判断题】
正弦交流电的周期与角频率的关系互为倒数的。
【判断题】
中间继电器实际上是一种动作与释放值可调节的电压继电器。
【判断题】
转子串频敏变阻器启动的转矩大,适合重载启动。
推荐试题
【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
【单选题】
Some old people don’t like pop songs because they cannot ___ so much noise.
A. resist
B. sustain
C. tolerate
D. undergo
【单选题】
I have kept that portrait where I can see it every day, as it always ___ me of my university days in London.
A. recollects
B. reminds
C. recalls
D. invokes
【单选题】
The article suggests that when a person is under unusual ___ he should be especially careful to have a well-balanced diet.
A. weight
B. stress
C. press
D. nerve
【单选题】
You should hire a more ___ manager than the one you currently have.
A. sufficient
B. effective
C. respective
D. efficient
【单选题】
Surgeons began to ___ their hands and arms with soap and water before operating.
A. scrub
B. enhance
C. rub
D. exhibit
【单选题】
He might let something ___ in a moment of weakness.
A. slip
B. leak
C. to slip
D. to leak
【单选题】
Do not ___ the salad until you are ready to serve.
A. mix
B. toss
C. fling
D. eat
【单选题】
The ___ for which he had fought all his life no longer seemed important to him.
A. aims
B. objectives
C. subjects
D. goals
【单选题】
You should pause and ___ now.
A. tweet
B. ponder
C. squander
D. gossip
【单选题】
Eating too much fat can ____heart disease and cause high blood pressure.
A. contribute to
B. attribute to
C. attest to
D. devote to
【单选题】
It soon ___ that what she loved was not my person but my wealth.
A. widened
B. expanded
C. extended
D. developed
【单选题】
I want to buy a new tie to ___ this brown suit.
A. go into
B. go after
C. go with
D. go through
【单选题】
Our company decided to ___ the contract because a number of the conditions in it had not been met.
A. destroy
B. resist
C. assume
D. cancel
【单选题】
My first ___ was to turn and run.
A. institute
B. institution
C. instinct
D. tuition
【单选题】
I think it’s time I ___ in a new computer.
A. invested
B. insulted
C. interacted
D. impacted
【单选题】
The jeweler will ____ the inside of the ring with her name.
A. carve
B. engrave
C. cut
D. engross
【单选题】
He was bleeding from a _____ on his forehead.
A. lash
B. gash
C. ash
D. sash
【单选题】
Let us go to the next ______ on the agenda.
A. matter
B. debate
C. speech
D. item
【单选题】
They are _____ moving their office outside London.
A. considered
B. discussing
C. pondering
D. negotiating
【单选题】
Although she _____ the old pot thoroughly, she could not make it look completely clean.
A. scrubbed
B. washed
C. made
D. screwed
【单选题】
The mistake will remain an indelible ____ on his memory.
A. stain
B. thing
C. issue
D. accident
【单选题】
The wheel ____ through my frozen hand, and the car went right across the road.
A. slipped
B. sipped
C. dashed
D. disappeared
【单选题】
The cupboard was ____ with old fishing tackle.
A. stuffed
B. stocked
C. stored
D. filled
【单选题】
The decision depended on the ____ of a coin.
A. loss
B. lot
C. toss
D. sign
