问题 选择题

关于磁感应强度,下列说法中正确的是(  )

A.磁感应强度的方向,就是通电直导线在磁场中的受力方向

B.磁感应强度大的地方,通电导线所受的安培力也一定大

C.通电导线在某处所受安培力为零,则该处的磁感应强度一定为零

D.在确定的磁场中,同一点的磁感应强度是确定的,不同点的磁感应强度可能不同,磁感线密的地方磁感应强度大些,磁感线疏的地方磁感应强度小些

答案

A、根据左手定则磁感应强度的方向与通电直导线在磁场中的受力方向垂直,故A错误;

B、当通电导线与磁场平行放置时,没有安培力.故B错误;

C、当某一面积与磁感线平行时,穿过面积的磁通量为零,则该处的磁感应强度并不一定为零,故C错误;

D、确定的磁场中,同一点的磁感应强度是确定的,不同点的磁感应强度可能不同,磁感线密的地方磁感应强度大些,磁感线疏的地方磁感应强度小些.故D正确;

故选:D

判断题
改错题

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第 Ⅱ 卷(共35分)

第四部分写作(共两节,满分35分)

第一节短文改错(共10小题;每小题1分,满分10分)

此题要求改正所给短文中的错误。对标有题号的每一行作出判断,如无错误,在该行右边的横线上画一个勾();如果有错误(每行只有一个错误),则按下列情况改正:

此行多一词:把多余的词用斜线(\)划掉,在该行右边横线上写出该词,并也用斜线划掉。

此行缺一词:在缺词处加一个漏字符号(∧),在该行右边横线上写出该加的词。

此行错一词:在错词下划一横线,在该行右边横线上写出改正后的词。

注意:原行没有错的不要改。

When people think about precious things, they usually                                  

think about money or jewelry. I am not very rich, and I have                          76. ___________      

something very preciously in my room. It’s not a CD player or                       77. ___________      

a cellphone. It's the view from my window. I’m lucky live                             78. ___________      

near a park. My window faces with the tops of the trees in                              79. ___________      

the park. Below the tree I can see children on the playground,                         80. ___________      

young couples walked quietly, mothers with children, and                              81. ___________      

old people sitting on the beach. The whole world is before                              82. ___________      

their eyes. My classmates like to go online or listen to music,                          83. ___________      

but when I have a free time, I just sit on the chair and                                    84. ___________      

enjoyed the most precious thing in my room: the view.                                  85. ___________