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问题 选择题

关于B=F/IL，下列正确说法的是：

A．磁感强度B与通电导体所受安培力成正比；

B．磁感强度B与通电导体长度和电流强度的乘积成反比；

C．公式表明磁感强度B的方向与通电导体的受力方向一致；

D．以上说法都不对。

答案

答案：D

题目分析：磁感强度为磁场本身的性质，与放不放导体棒没有关系，公式B=F/IL只是计算式，不是决定式，AB错；安培力的方向总是垂直与BI所构成的平面，C错；故选D

点评：难度较小，要明白磁感强度为磁场本身的性质，与放不放导体棒没有关系

单项选择题

So it is today. Schedule disaster, functional misfits, and system bugs all arise because the left hand doesn’t know what the right hand is doing. As work （）, the several teams slowly change the functions, sizes, and speeds of their own programs, and they explicitly or implicitly （） their assumptions about the inputs available and the uses to be made of the outputs. For example, the implementer of a program-overlaying function may run into problems and reduce speed relying on statistics that show how （） this function will arise in application programs. Meanwhile, back at the ranch, his neighbor may be designing a major part of the supervisor so that it critically depends upon the speed of this function. This change in speed itself becomes a major specification change, and it needs to be proclaimed abroad and weighed from a system point of view. How, then, shall teams （） with one another In as many ways as possible. Informally. Good telephone service and a clear definition of intergroup dependencies will encourage the hundreds of calls upon which common interpretation of written documents depends. Meetings. Regular project meetings, with one team after another giving technical riefings, are（）. Hundreds of minor misunderstandings get smoked out this way. Workbook. A formal project workbook must be started at the beginning.

Regular project meetings, with one team after another giving technical riefings, are（）. Hundreds of minor misunderstandings get smoked out this way

A．worthless

B．valueless

C．useless

D．invaluable
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填空题

激波角将随气流M数的增大而（）。
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