【单选题】如图所示,载流线圈在均匀磁场中所受的磁力矩方向是
【单选题】以《全国统一建筑工程量计算规则》为依据,现浇整体楼梯的混凝土工程量按()计算。
【判断题】数据库服务与Web服务器需要在同一台计算机上。
【判断题】数据库服务与 Web 服务器需要在同一台计算机上
【单选题】What does the passage say about the Industrial Revolution? ______.
A.
Unlike other revolutions, it was an event without a fairly clear end.
B.
Unlike other revolutions, it did not bring about major social changes.
C.
It was not a revolution in the true sense of the word.
D.
Its influence was limited to industry and economy.
【简答题】一半径为R的圆形线圈.其有N匝.载有电流为I,放在均匀外磁场B中,如图所示.求 (1)载流线圈所受的磁力矩; (2)在该力矩作用下,线圈转了90°,求磁力矩作的功。