两个铁心线圈除了匝数不同（N1>N2）外，其他参数都相同，若将这两个线圈接在同一交流电源上，他们的磁通φ1和φ2的关系为
A
暂无解析
InthenortheasternUnitedStates,itrainsintermittently间歇地throughoutthespring.
Communicationisoneofthemostimportantbondsthatholdculturalsystemstogether.
Urbanrenewalprogramsstrivetoupgradeareasthatarebecomingslums.
设随机变量X，若D(X)=3，则D(一X+3)=()．
ThefirstimportantexpositionintheUnitedStateswasheldinPhiladelphiain1876.
