【判断题】在歌唱中保持气息一直向前走的状态是正确的么?A. 正确B. 不正确
【简答题】导线 长为 ,绕过 点的垂直轴以匀角速 转动, = 磁感应强度 平行于转轴,如图所示.试求: (1) 两端的电势差; (2) 两端哪一点电势高?
【单选题】I have collided with unknown object
A.
The vessel is in collision with unknown vessel
B.
The vessel is in collision with unknown object
C.
The vessel is in collision with a seamark
D.
The vessel is in collision with a light vessel
【简答题】(10分)导线 长为 ,绕过 点的垂直轴以匀角速 转动, = ,磁感应强度 平行于转轴,如图所示.试求: (1)ab 两端的电势差; (2)a,b 两端哪一点电势高?