【单选题】
电流是由电子的定向移动形成的,习惯上把( )定向移动的方向作为电流的方向。(易)  
A.  N-S
B.  右手定则
C.  正电荷
D.  左手定则
查看试卷,进入试卷练习
微信扫一扫,开始刷题
答案
C
解析
暂无解析
相关试题
【单选题】
29、电流的大小用电流强度来表示,其数值等于单位时间内穿过导体横截面的()代数和。(中)
A. 电流强度
B. 电流
C. 电量(电荷)
D. 功率
【单选题】
30、导体的电阻不但与导体的长度、截面有关,而且还与导体的()有关。(中)
A. 距离
B. 湿度
C. 材质
D. 电压
【单选题】
31、并联电路中, 电流的分配与电阻成( )。(易)
A. 反比
B. 正比
C. 1:1
D. 2:1
【单选题】
32、磁通的单位是(  )。(易
A. Wb
B. B
C. TD
D. MB
【单选题】
33、串联电路具有以下特点( )。(易)  
A.  各电阻上消耗的功率之和等于电路所消耗的总功率 
B. 各电阻上分配的电压与各自电阻的阻值成正比。
C. 串联电路中各电阻两端电压相等
D. 流过每一个电阻的电流不相等
【单选题】
24、1安培等于()微安。(易)
A. 10³
B. 10的6次方
C. 10的9次方
D. 10²
【单选题】
27、电路主要由负载、线路、电源、( )组成。(易)
A. 发电机
B. 变压器
C. 开关
D. 仪表
【单选题】
26、额定电压为220V的灯泡接在110V电源上,灯泡的功率是原来的( )。(难)
A. 4
B. 1/4
C. 1/2
D. 2
【单选题】
25、将一根导线均匀拉长为原长度的3倍,则阻值为原来的( )倍。(难)
A.  1/3    
B. 9
C. 3
D. 1/9
【单选题】
由___、负载、开关经导线连接而形成的闭合回路称之为电路。(易)
A. 电源
B. 电压
C. 电流
D. 电子
【单选题】
电源是提供___的装置.(易)
A. 电能
B. 电子
C. 交流电
D. 直流电
【单选题】
为了准确地衡量某一时刻电流的大小或强弱,引入了___这个物理量。(易)
A. 电流强度
B. 电压
C. 电流量
D. 电压强度
【单选题】
电动势的单位是___。(易)
A. 伏特
B. 安培
C. 欧姆
D. 瓦特
【单选题】
___是衡量电场作功本领大小的物理量。(易)
A. 电流强度
B. 电流
C. 电子
D. 电压
【单选题】
电压的单位是___。(易)
A. 安培
B. 欧姆
C. 瓦特
D. 伏特
【单选题】
电阻常用字母R表示,其单位是___。(易)
A. 瓦特
B. 伏特
C. 安培
D. 欧姆
【单选题】
金属导体电阻的大小与导体长度成___,与横截面积成( )。(中)
A. 反比 反比
B. 反比 正比
C. 正比 正比
D. 正比 反比
【单选题】
电阻器是利用___材料的电阻特性制成的器件。(易)
A. 合成
B. 金属
C. 非金属
D. 金属或非金属
【单选题】
欧姆定律是反映___三者之间关系的基本定律。(易)
A. 电压 电流 电子
B. 电压 电子 电阻
C. 电子 电流 电阻
D. 电压 电流 电阻
【单选题】
当温度不变时,流过导体的电流与这段导体两端的电压成___,与这段导体的电阻成( )。(易)
A. 正比 正比
B. 反比 正比
C. 反比 反比
D. 正比 反比
【单选题】
沿电流流动的力向,在电阻上必然产生电压降,此压降与___成正比。(易)
A. 电压
B. 电流
C. 电压和电流
D. 电流和电阻
【单选题】
全电路是含有电源的___。(易)
A. 闭合电路
B. 串联电路
C. 并联电路
D. 混联电路
【单选题】
全电路欧姆定律的内容是:全电路中的电流与电源的电动势成___,与整个电路(即内电路和外电路)的总电阻成( )。(易)
A. 正比 反比
B. 反比 反比
C. 正比 正比
D. 反比 正比
【单选题】
电路接通时电源两端的电压,通常简称___。(易)
A. 端电压
B. 外电压
C. 总电压
D. 负电压
【单选题】
几个电阻的首尾依次相连,中间没有分支,只有一条电流通路。这种连接方式称为电阻的___。(易)
A. 串联电路
B. 并联电路
C. 混联电路
D. 集成电路
【单选题】
串联电路中,某一电阻值与总电阻值之比,称为分压比(或分压系数),用字母___表示。(易)
A. “K”
B. “I”
C. “U”
D. “R”
【单选题】
电阻值越大分配电流越___,电阻值越( )分配电流越大。(易)
A. 小 小
B. 大 小
C. 大 大
D. 小 大
【单选题】
蓄电池的容量,是在放电允许范围内,蓄电池所输出的电量,它表示蓄电池的供电能力,用字母___表示。(易)
A. “I”
B. “Q”
C. “U”
D. “K”
【单选题】
“I”的单位是___,“t”的单位是( ),“Q”的单位是( )。(易)
A. 小时(h) 安(A) 安时(Ah)
B. 安(A) 小时(h) 安时(Ah)
C. 安时(Ah) 安(A) 小时(h)
D. 小时(h) 安时(Ah) 安(A)
【单选题】
电荷的基本单位是___。(易)
A. 安培
B. 库仑 
C. 安秒
D. 千克
【单选题】
电池___后,总内阻等于各单个电池内阻之和。(易)
A. 串联
B. 并联
C. 混联
D. 都对
【单选题】
电功的单位是___。(易)
A. 焦耳
B. 安培
C. 伏特
D. 瓦特
【单选题】
电功用字母___表示。(易)
A. “J”
B. “I”
C. “U”
D. “R”
【单选题】
电功率是单位时间内电场力所作的功或单位时间内消耗在电路内的___。(易)
A. 电能
B. 电子
C. 电流
D. 能量
【单选题】
电功率,单位是___。(易)
A. 瓦特
B. 伏特
C. 安培
D. 欧姆
【单选题】
电流表和电压表是最常用的电工仪表,分别用来测量___和( )。(易)
A. 电流 电压
B. 电压 电流
C. 电子 电流
D. 电压 电子
【单选题】
液压泵是将电动机输出的机械能转换成___的能量转换装置。(易)
A. 电能
B. 热能
C. 磁能
D. 液体压力能
【单选题】
液压泵能实现吸油和压油,是由于泵的___变化。(易)
A. 动能
B. 压力能
C. 密封容积
D. 流动方向
【单选题】
液压油___,常常是液压系统发生故障的主要原因。(易)
A. 温度过高
B. 粘度太小
C. 粘度太大
D. 受到污染
【单选题】
旁路节流调速回路在___时有较高的速度刚度。(中)
A. 重载高速
B. 重载低速
C. 轻载高速
D. 轻载低速
推荐试题
【单选题】
-How about going fishing?___, I have no patience for that.
A. Excuse me
B. Sorry
C. Pardon
D. Apologize
【单选题】
- Thanks for the lovely and delicious food______.
A. No thanks
B. Never mind
C. All right
D. My pleasure
【单选题】
- Haven't seen you for ages. Let's have a get-together next week._____
A. Great idea.
B. Welcome!
C. Yes, of course.
D. No, thanks.
【单选题】
- Do you mind if I switch off the radio? ______. Go ahead.
A. Never mind
B. No way
C. No, not at all
D. No, you'd better not
【单选题】
- Could I use your bike for a moment? ___
A. It's well.
B. It doesn't matter.
C. By all means.
D. I have no idea.
【单选题】
-How do you like the story?_______.
A. I'd like to read it
B. I like it very much
C. fine, thank you
D. It's very interesting
【单选题】
- I'll sorry to trouble you.______.
A. Don't say so
B. OK
C. It doesn't matter
D. That's fight
【单选题】
- We ordered 20 boxes of your products, but we have only got 19. - ____
A. You do not have to.
B. It does not matter.
C. We will send another tomorrow.
D. Nothing serious.
【单选题】
--Will you please give the note to him? _________.
A. Certainly, I'll give it to him
B. No, please not
C. Sorry, I don't
D. Yes, please do
【单选题】
- Thank you ever so much for your lovely gift____
A. Never mind
B. I'm glad you like it.
C. Please don't say so.
D. No, It's not so good.
【单选题】
- I'd like to invite you to dinner this Saturday, Mr. Smith.____
A. Oh, no. let's not.
B. I'd rather stay at home.
C. I'm sorry, but I have other plans.
D. Oh, no. That'll be too much trouble.
【单选题】
- Could you please open the window?____
A. I can't.
B. Go ahead.
C. Sure.
D. It's really very kind.
【单选题】
- Do you think I can borrow your bike for a few hours?____
A. I'm afraid you can.
B. I'm sorry, but I really need it this afternoon.
C. Yes, I don't think so.
D. I'll think about it later.
【单选题】
- Thank you very much for the dictionary you sent me.____
A. No thanks.
B. I'm glad you like it.
C. Please don't say so.
D. No, it's not so good.
【单选题】
- How do you like the movie we saw yesterday?____
A. You are welcome.
B. How about you?
C. I've never seen a better movie than it.
D. It is very expensive.
【单选题】
- What do you think of your new teacher____
A. He came to teach us last week.
B. He teaches us English.
C. He has two children.
D. He is very nice.
【单选题】
- Are you going to have a holiday?____
A. Not until next week.
B. Three weeks ago.
C. To Beijing.
D. I'm pleased to hear that.
【单选题】
- You seem to be lost. Need help? ____
A. Yes, would you please help me with the bag?
B. Help me find my key, please.
C. Yes, with pleasure.
D. I'm looking for Zhongshan Road.
【单选题】
- Can you help me clear up the mess____
A. Yes, it doesn't matter.
B. No, that's OK.
C. Yes, help yourself.
D. No problem.
【单选题】
- Does No.20 bus stop at our school?____
A. I go to school by bus.
B. I'm afraid not.
C. You are welcome.
D. I'll not take No.20 bus.
【单选题】
- Can I help you? ____
A. Sorry, I don't need your help.
B. What help can you give us?
C. I'd like to try on these shoes, please.
D. Thanks. You are welcome.
【单选题】
- Sorry to have kept you waiting. ____
A. That's OK.
B. What are you doing?
C. What's wrong with you?
D. Where have you been?
【单选题】
- What is she?____
A. She is a typist.
B. She is talking to her friend.
C. She is having a holiday.
D. She is my sister.
【单选题】
- That's a beautiful cat. I wonder who it belongs to.____
A. It belongs to the
B. rowns. B.The cat is my favourite too.
C. Mind your own business.
D. I can't say anything more.
【单选题】
- Excuse me, could you tell me the time____
A. You'd better buy a watch.
B. It's three thirty by my watch.
C. Can you see the clock?
D. It's late I think.
【单选题】
- What do you think of the movie we saw last night?____
A. The actress is bad.
B. Terrific!
C. The theatre is bad.
D. Nobody was there.
【单选题】
___ No, thanks. I'm just looking around. I'll let you know if I want anything.
A. Could you help me?
B. What will you buy?
C. Can I help you?
D. Do you like to look around?
【单选题】
- Hello, Peter. What do you do?____
A. I am fine.
B. I am not sick.
C. I am a student from Bonn University.
D. I came from Bonn University.
【单选题】
-Excuse me; can I have a seat here?___
A. Be hurry.
B. Come on.
C. Yes, please.
D. Do you mind?
【单选题】
- Shall we sit up here on the grass or down there near the water?___
A. I'd rather stay here if you don't mind.
B. Sorry, I don't like neither.
C. Certainly, why not?
D. Yes, we like these two places.
【单选题】
- What do you do on Sunday?___
A. I 'm a teacher.
B. I play football.
C. You are a student.
D. They clean rooms.
【单选题】
- Our class won the girls' relay race in our school's sports meeting.___
A. That's right.
B. Thanks a lot.
C. Congratulations!
D. It's a pleasure.
【单选题】
- Hi, is Mary there, please?___
A. Hold on. I'll get her.
B. No, she isn't here.
C. Yes, she lives here.
D. Yes, what do you want?
【单选题】
- I am afraid I can't return the book to you before Friday. ___
A. Don't be afraid
B. Be careful
C. Not at all
D. Take your time
【单选题】
- I really don't know how to thank you enough. ___.
A. No problem
B. Think nothing of it
C. Not at all
D. It doesn't matter
【单选题】
- Must I be home before seven? ___.
A. No, you needn't
B. No, you mustn't
C. Yes, you will
D. No, you won't
【单选题】
-I'm sorry to hear that you failed in the exam______.
A. Not at all
B. Oh, thank you.That's very kind of you
C. You are welcome
D. Yes, I'm really sorry
【单选题】
-I will,______.
A. that's all right
B. thank you
C. all right
D. not at all
【单选题】
-Hello, may I speak to Zhao Hua?_____.
A. My name is Zhao Hua
B. I'm Zhao Hua
C. This is Zhao Hua speaking
D. Zhao Hua is me
【单选题】
___This is Mr Smith speaking now.
A. Who are you
B. Who is that
C. Who are you calling
D. What do you want to say