【单选题】如图所示的装置是半径为R的半圆形导线,在磁感应强度为B的均匀磁场中以频率f旋转.设电表M的内电阻为RM,而电路其余部分的电阻忽略不计,则【图片】
【多选题】如图所示,设圆柱面半径为 R ,电流均匀的分布在导体的外表面上。求无限长载流圆柱面内、外磁场的磁感应强度大小分别为( )
【单选题】Mr.brown found the plant_________ to grow.
【单选题】Read the following text with five gaps. Choose the best sentence or phrase from the list A~F. (There is one extra item.) For gaps 1~5, mark one letter (A~F) to fill each of the gaps. Do not mark any l...
A.
prevent the packaged goods from any damage
B.
some special cases and with unique packages
C.
serve several primary functions
D.
get the contents into a nice, compact shape
E.
its choice of color, design, shape and texture
F.
various forms and with different materials
【单选题】Mr.Brown found the plant ___to grow.
【单选题】如图所示,设均匀磁场的磁感应强度为B,导体的长度为L,则导体的受力方向____、受力大小为____。
【单选题】I’m Mr. Brown from the police station. Could you tell me _____the butcher found moving slowly across the square?
【判断题】受客流分布以及地铁修建的周边条件等的因素的影响,地铁主要有三种形式。即:地下线、地面线、高架线;对应的车站为:地下站、地面站、高架站。