【单选题】
电路处于断路状态时,电路中没有 ___ 流过。
A. 电压
B. 电流
C. 电阻
查看试卷,进入试卷练习
微信扫一扫,开始刷题
答案
B
解析
暂无解析
相关试题
【单选题】
已知一部分电路的端电压为10V,电阻为 5?,则电流的电流为___A 。
A. 1
B. 2
C. 5
【单选题】
在纯电阻电路中,电流和电压 ___ 。
A. 同相位
B. 反相位
C. 相位差为π /2
【单选题】
在实际应用中,常用 ___定为设备的额定容量,并标在铭牌上。
A. 有功功率P
B. 无功功率Q
C. 视在功率S
【单选题】
在三相交流电路中,负载消耗的总有功功率等于___ 。
A. 各相有功功率之差
B. 各相有功功率之和
C. 各相视在功率之差
【单选题】
同性磁极相互___ 。
A. 吸引
B. 排斥
C. 无作用力
【单选题】
全电路欧姆定律表明,在闭合回路中,电流的大小与电源电动势___, 与整个电路的电阻成反比。
A. 成正比
B. 成反比
C. 正弦规律
【单选题】
下列关于保护变压器的角型间隙安装位置描述正确的是___ 。
A. 远离变压器一侧
B. 高压熔断器的外侧
C. 高压熔断器的内侧
【单选题】
金属氧化锌避雷器特点有动作迅速、___ 、残压低、通流量大。
A. 无续流
B. 能耗低
C. 续流小
【单选题】
线路验电应逐相进行。同杆架设的多层电力线路验电时,先验低压后验高压、___。
A. 先验上层后验下层
B. 验下层
C. 先验下层后验上层
【单选题】
如果在交接班过程中,有异常情况要处理,仍由 ___ 负责处理 ,必要时可请接班人员协助工作。
A. 交班人员
B. 接班人员
C. 调度员
【单选题】
RN2 型高压熔断器可适用于作___的保护。
A. 变压器
B. 电力线路
C. 电压互感器
【单选题】
值班人员发现任何异常现象应及时消除,不能及时消除时,除及时报告上级领导外,还应记入运行记录簿和___ 。
A. 检修记录簿
B. 缺陷记录薄
C. 事故记录薄
【单选题】
隔离开关作用之一是___ 。
A. 隔离电源
B. 隔离电流
C. 隔离电场
【单选题】
交流真空接触器-熔断器组合电器,___ 的使用空间。
A. 限制了接触器
B. 拓展了接触器
C. 限制了熔断器
【单选题】
SF6 负荷开关的灭弧能力较SF6 断路器 ___ 。
A. 强
B. 弱
C. 相同
【单选题】
隔离开关按刀闸运动方式分类可分为___、垂直旋转式和插入式。
A. 360 旋°转式
B. 捆绑式
C. 水平旋转式
【单选题】
高压熔断器以动作特性可分为___ 和固定式。
A. 自动跌落式
B. 插入式
C. 非限流式
【单选题】
隔离开关的主要作用之一是___ 。
A. 倒闸操作
B. 隔离电流
C. 拉合负荷电流
【单选题】
SF6 断路器的缺点之一是,SF6 气体在电弧的作用下分解的___ 气体有毒。
A. 硫化物
B. 氧化物
C. 低氟化物
【单选题】
一般隔离开关没有灭弧装置,不允许它 ___ 分、合闸操作。
A. 空载时进行
B. 母线切换
C. 带负荷进行
【单选题】
对于中、小容量变压器,可以装设单独的___, 作为变压器防止相间短路故障的主保护。
A. 电流速断保护
B. 过电流保护
C. 差动保护
【单选题】
下列 ___表示时间继电器。
A. K
B. KS
C. KT
【单选题】
轻瓦斯动作后,___ 。
A. 跳开变压器高压侧断路器
B. 跳开变压器低压侧断路器
C. 只发信号 ,不跳开关
【单选题】
___ 指正常情况下有明显断开的备用电源或备用设备或备用线路。
A. 明备用
B. 冷备用
C. 暗备用
【单选题】
设备编号中 ,罗马数字表示___ 。
A. 设备顺序号
B. 设备数量
C. 安装单位编号
【单选题】
对于较为重要、容量较大的变电所,操作电源一般采用___ 。
A. 直流操作电源
B. 交流操作电源
C. 逆变操作电源
【单选题】
电力线路保护属于按___ 分类。
A. 被保护的对象
B. 保护原理
C. 保护所起作用
【单选题】
把设备编号和接线端子编号加在一起,每一个接线端子就有了唯一的___ 。
A. 设备文字符号
B. 回路编号
C. 相对编号
【单选题】
小母线编号中,符号 “~”表示 ___性质。
A. 正极
B. 负极
C. 交流
【单选题】
重瓦斯动作后,跳开变压器 ___ 断路器。
A. 高压侧
B. 两侧
C. 低压侧
【单选题】
___的绝缘强度不能承受电气设备或线路的工作电压,只能起加强基本安全用具的保护作用。
A. 绝缘安全用具
B. 一般防护安全用具
C. 辅助安全用具
【单选题】
由于手持式电工工具在使用时是移动的,其电源线易受到拖拉、磨损而碰壳或脱落导致设备金属外壳带电,导致 ___ 。
A. 触电事故
B. 断电事故
C. 短路事故
【单选题】
绝缘靴 (鞋)属于 ___。
A. 绝缘安全用具
B. 一般防护安全用具
C. 辅助安全用具
【单选题】
使人体能够感觉到的最小电流称为___ 。
A. 感知电流
B. 持续电流
C. 致命电流
【单选题】
绝缘靴 (鞋)要定期试验 ,试验周期一般为___个月。
A. 1
B. 3
C. 6
【单选题】
___ 用具是登高作业时必须必备的保护用具。
A. 登高板
B. 安全带
C. 脚扣
【单选题】
下列 ___ 的连接方式称为保护接地。
A. 将电气设备金属外壳与中性线相连
B. 将电气设备金属外壳与接地装置相连
C. 将电气设备金属外壳与其中一条相线相连
【单选题】
高压电气设备停电检修时,为防止检修人员走错位置,误入带电间隔及过分接近带电部分 ,一般采用 ___ 进行防护。
A. 绝缘台
B. 绝缘垫
C. 遮拦
【单选题】
作为电气工作者,员工必须熟知本工种的___ 和施工现场的安全生产制度,不违章作业。
A. 生产安排
B. 安全操作规程
C. 工作时间
【单选题】
绝缘安全用具分为___ 。
A. 一般防护安全用具和接地装置
B. 基本安全用具和辅助安全用具
C. 辅助安全用具和接地装置
推荐试题
【单选题】
( ) 40. The best title of the passage is ___________. A. Rivers in Cities B. The importance of Rivers C. Transportation D. Natural Resources
A. A
B. B
C. C
D. D
【单选题】
) 1. Even Tony’s six-year-old son asked him ______ smoking. A. stops B. stopped C. to stop D. stopping
A. A
B. B
C. C
D. D
【单选题】
2.—What do you think of the lecture of Li Yang’s Crazy English? — I think it’s _______ , but someone thinks it’s much too ________. A. wonderful enough; bored B. enough wonderful; boring C. enough wonderful; bored D. wonderful enough; boring
A. A
B. B
C. C
D. D
【单选题】
3.—He didn’t go to the lecture this morning, did he?    — _____ .Though he was not feeling very well. A. No, he didnt B. Yes; he did C. No, he did D. Yes, he didnt
A. A
B. B
C. C
D. D
【单选题】
4. If you read a lot, your life ______ full of pleasure. A. will be B. is C. be D. was
A. A
B. B
C. C
D. D
【单选题】
5. The black bag _________ be Annas. She has a blue one. A. should B. cant C. wouldnt D. could
A. A
B. B
C. C
D. D
【单选题】
6. Susan, why are you still here? They are all ready to start. Im sorry, but I _________ when to start. A. dont tell B. wasnt told C. didnt tell D. havent told
A. A
B. B
C. C
D. D
【单选题】
7.—Why dont you choose the red tie?    —For me, it doesn’t _____ my shirt very well. A. fix B. accept C. compare D. match
A. A
B. B
C. C
D. D
【单选题】
8. — Could you tell me ______? I must find him. — Sorry.I don’t know.But he was here just now. A. where Tom was B. where Tom is C. where has Tom gone D. where can I find Tom
A. A
B. B
C. C
D. D
【单选题】
9. —What did Mr Green say to you? — What a heavy rain! How did you come here? He asked________. A. at all B. in fact C. in surprise D. as a result
A. A
B. B
C. C
D. D
【单选题】
10. I often see Tom on the playground.When I passed the playground yesterday, I saw him . A. play; playing B. to play; play C. playing; to play D. playing; play
A. A
B. B
C. C
D. D
【单选题】
11. — Mum, could I have ____________ to drink? — Oh, dear.You can only drink some water.There is _________ in the kitchen. A. anything; else something B. anything; something else C. something; else nothing D. something; nothing else
A. A
B. B
C. C
D. D
【单选题】
12. We all know that learning a foreign language _______ time and effort. A. requires B. reduces C. removes D. repeats
A. A
B. B
C. C
D. D
【单选题】
13. Her son __________ Coke, but now he __________ milk. A. is used to drinking; used to drink B. used to drink; uses to drink C. used to drink; is used to drinking D. is used to drink; is drinking
A. A
B. B
C. C
D. D
【单选题】
14. I don’t know the teacher is talking with Miss Wang. A. what B. whom C. who D. which
A. A
B. B
C. C
D. D
【单选题】
15.Millie does __________ that many people are thankful to her. A. such an important and helpful job B. so important and helpful work C. a very important and helpful job D. such an important and helpful work
A. A
B. B
C. C
D. D
【单选题】
16. I think eating more vegetables is good _______ our health. —Yes, I agree _______ you. A. at, to B. for, with C. to, to D. for, to
A. A
B. B
C. C
D. D
【单选题】
17. I often go on holiday with my parents _____ summer. A. in B. at C. on D. of
A. A
B. B
C. C
D. D
【单选题】
18. I called you at 4:00 yesterday afternoon, but nobody answered. Sorry, I ______ with my friends at that time. A. had swum B. swam C. would swim D. was swimming
A. A
B. B
C. C
D. D
【单选题】
19.––Who is on the playground? ---__________.    A. Never B. None C. No one D. A lot
A. A
B. B
C. C
D. D
【单选题】
20. The schoolboy ______ a blind man cross the street yesterday. A. helps B. helped C. will help D. has helped
A. A
B. B
C. C
D. D
【单选题】
21. —The 2010 World Expo which will last 184 days will be held in Shanghai on May 1st. —________exciting news! We shall try our best to support it. A. How B. How an C. What D. What an
A. A
B. B
C. C
D. D
【单选题】
22. They preferred ______ in bed rather than _____ horses.    A. to lie; to ride B. lying; riding C. lying; ride D. to lie; ride
A. A
B. B
C. C
D. D
【单选题】
23. —What was Jim wearing at the party? — Nothing _______. He was in his usual shirt and jeans. A. special B. simple C. important D. interesting
A. A
B. B
C. C
D. D
【单选题】
24. The 2016 Olympic Games ________ in Brazil. Would you like to go there? Maybe, if possible. A. are held B. will be held C. were held D. have been held
A. A
B. B
C. C
D. D
【单选题】
25. — David, look at the man in white over there.Can you tell me _______ ? —He is a doctor.    A. who is he B. who he is C.what does he do D. what he does
A. A
B. B
C. C
D. D
【单选题】
( ) 26.With help from a Mr. H, you can__________. A. stop wearing your watch B. get new books and objects C. finish your homework on time D. know when parents or teachers are near
A. A
B. B
C. C
D. D
【单选题】
( ) 27. A PENGO WATCH CONTROL can help you to ______________. A. repair your TV B. put away your books and objects C. become a James Bond D. get a daily weather report
A. A
B. B
C. C
D. D
【单选题】
( ) 28. You can get your Mr. H for___________. A. $299 B. $499 C. $199 D. $99
A. A
B. B
C. C
D. D
【单选题】
( ) 29. When was canned food invented? A. In 1870.          B. In 1810. C. In 1902.          D. In 1926.
A. A
B. B
C. C
D. D
【单选题】
( ) 30. After the trip to the Arctic, Clarence Birdseye invented ____________. A. canned food             B. can openers C. frozen food           D. air conditioning
A. A
B. B
C. C
D. D
【单选题】
( ) 31. Changes in weather _____________ in Willis Carrier's company. A. helped to keep food           B. made rooms comfortable C. caused health problems        D. hurt printing paper
A. A
B. B
C. C
D. D
【单选题】
( ) 32. According to the passage, which of the following may lead to inventions? A. People's needs.             B. Public support. C. Modern technology.          D. Practical suggestions.
A. A
B. B
C. C
D. D
【单选题】
( ) 33. What is the writer's main purpose(目的)in writing this passage?    A.To tell the readers his life story.    B.To tell people what kind of person his father was.    C.To tell the readers what present he got from his father.    D. To let people know how poor he was.
A. A
B. B
C. C
D. D
【单选题】
( ) 34. Why did the father not ask his son not to do this and do that?    A.Because he felt quite confident of his son.    B.Because he was born from a poor family.    C.Because he was a man of few words.    D.Because he didn't want to be much too strict with his son.
A. A
B. B
C. C
D. D
【单选题】
( ) 35. What would someone learn from this passage?    A.How to live by oneself. B.How to stand on one's own feet.    C.What a good father should do. D.What the self-important is like.
A. A
B. B
C. C
D. D
【单选题】
( ) 36. What may be the proper Chinese for the underlined part in the passage?    A.闲暇时光 B.学费 C.精神空虚 D.经济不足
A. A
B. B
C. C
D. D
【单选题】
( ) 37. The Chinese Yellow Sea Wetlands are in the _______ of China.    A.south           B.east    C.west            D.north
A. A
B. B
C. C
D. D
【单选题】
( ) 38. Usually the weather in the wetlands is _______.    A.hot             B.pleasant   C.cold            D.dry
A. A
B. B
C. C
D. D
【单选题】
( ) 39. The World Wetlands Day is on _______.    A.February 2        B.June 25   C.April 22      D.March
A. A
B. B
C. C
D. D