题目

如下图所示的四个演示实验中，能够说明发电机原理的是（ ）A. B.C. D. 答案：【答案】D【解析】A．此图中甲、乙是两个匝数不同的线圈，二者串联在电路中，流过它们的电流相同，此演示实验能够说明电流相同时，通电线圈的匝数越多，它吸引的大头针越多，它的磁性越强，故A不符合题意；B．此演示实验，闭合开关，导体AB在磁场中受力产生运动；改变导体AB的电流方向，AB向5．-Hello．Gerry speaking．-Hello，Gerry．It's me John here．（61）C．-Well，I'm terribly sorry，but I'm not feeling very well．-Is that all？（62）E-No，I'm sorry．I was sick all night．I think it must be the fish I ate last night-Well，I think you should have at least phoned Kate and told her you weren't coming to the meeting．-（63）GI'm sorry about that．Anyway，I think I'll be able to get in to work tomorrow．-（64）BI won't..Thanks for calling．-（65）D．A．Why didn't you phone？B．OK．Take care and don't eat any more fish．C．Why weren't you here at the meeting？D．That's all right．E．We thought you might have had an accident or forgotten the day or something．F．I'll be glad to see you again．G．Yes，I suppose I should have done so．