如图,电源电动势为30V,内电阻不计,一个“6V12W”的电灯与一个绕线电阻为2 发布时间:2017-05-17 18:29 │ 来源:www.tikuol.com 题型:问答题 问题: 如图,电源电动势为30V,内电阻不计,一个“6V 12W”的电灯与一个绕线电阻为2Ω的电动机M串连接入电路.已知电路中电灯正常发光,则电动机输出的机械功率为多少?
题型:问答题 用方框内所给单词的适当形式填空,使短文意思通顺、正确。每词限用一次。want, your, visitor, between, any In England, afternoon tea is the most informal (非正式) meal of a day. It is usually 1______ 4:00 and 5:00. If you are a friend of the family, you may come for tea at 2______ time. Very often it is not taken at a table. The members of the family and 3______ take the tea in the sitting room. Each person has a cup, a saucer (茶盘), a spoon and a small plate for bread and butter and cakes. By the way, do not help 4______ to cakes first, but bread and butter first, and then cakes. Do remember: though you can eat as much as you 5______, do not put more than one piece of bread or cake on your plate each time. 查看答案
题型:问答题 一段长0.2 m,通过2.5 A电流的直导线,关于在磁感应强度为B的匀强磁场中所受安培力F的情况,正确的是 A.如果B=2 T,F一定是1 NB.如果F=0,B也一定为零C.如果B=4 T,F有可能是1 ND.如果F有最大值时,通电导线一定与B平行 查看答案
题型:问答题 下图为某县1963年设县开始到1975年时的城市简图,读图回答:(1)将县设置在该地区的原因是A.该地为水陆交通枢纽的地区 B.地形平坦、水运便利、有充足的水源C.有丰富的石油资源 D.有丰富的水能资源(2)该地的水运码头十分优良,几十年来没有淤积现象,其原因可能是A.该河段位于三峡峡谷地区,水流湍急 B.由于地转偏向力的影响,河流向右偏,冲积北岸所致C.由于地转偏向力的影响,河流向左偏,冲积北岸所致 D.处于河流的凹岸,河水冲刷严重(3)化肥厂的原料—石油通过管道输送到车间是十分合适的一种设计方案,但下列关于其优点的叙述中有一项是不正确的是A.设备投资小,灵活性好 B.石油不外漏、损耗小C.连续性强、可以昼夜不停的运输,运量很大 D.平稳安全,管理方便 查看答案