题目: _ we left the building that I realized how dangerous the situation had been.A.Only thenB.It was only thenC.Only afterD.It was only after 答案: 答案:D
题型:选择题 Mr.White is now in Beijing and runs a company ________ in Zhongguancun together with some Chinese friends.A.to baseB.basingC.to be basedD.based 查看答案
题型:多选题 如图所示,一个有界匀强磁场区域,磁场方向垂直纸面向外.一个矩形闭合导线框abcd,沿纸面由位置1(左)匀速运动到位置2(右).则( )A.导线框进入磁场时,感应电流方向为a→b→c→d→aB.导线框离开磁场时,感应电流方向为a→b→c→d→aC.导线框全部进入磁场运动时,感应电流方向为a→b→c→d→aD.导线框全部进入磁场运动时,导线框中没有感应电流 查看答案
题型:计算题 如图18所所示,矩形线圈abcd长、宽为,匝数为,在磁感应强度的匀强磁场中绕其轴线以角速度做匀速转动:(1)求线圈中交变电动势的最大值和有效值?(2)求此交变电动势的周期?(3)从图中位置开始计时,求末线圈内的电动势? 查看答案