【单选题】如下错误的为()。
A.
在电力系统中发生并联谐振时,在电感和电容元件中会流过很大的电流。
B.
所谓相序就是三相交流量在变化过程中到达最大值或零值的先后顺序。
C.
正弦交流电是指其大小和方向随时间按正弦函数规律做周期性变化的电势、电压与电流。
【单选题】时谐电磁场是指随时间按( )变化的时变电磁场。
【单选题】婴儿最早说出第一个有意义的词语的年龄为:
【简答题】For many students in the UK today, deciding whether or not to go to university can be as much about affordability as it is about ambition and aspiration. In the past, students in the UK could apply to...
【多选题】下列关于时谐电磁场说法正确的是( )
A.
随时间按正弦(或余弦)规律作简谐变化的电磁场,称为时谐电磁场或正弦电磁场
B.
时谐场是指不包含时间因子exp(jωt)的场
C.
一些非简谐的电磁波可以通过傅里叶变换变换成正弦电磁波来研究
【简答题】If Aristotle wanted to work in a university in the UK today, he would have a good chance of teaching computer science but would not be so readily employable as a philosopher. ( Passage 2)