均匀磁场的磁感强度B垂直于半径为r的圆面。今以该圆周为边线，作_爱下问搜题

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问题单项选择题

均匀磁场的磁感强度B垂直于半径为r的圆面。今以该圆周为边线，作一半球面S，则通过S面的磁通量的大小为______。

A．2r²B
B．πr²B
C．0
D．无法确定的量

答案

参考答案：B

解析：半球面在垂直磁场方向上的投影面即为半径r的圆，故可知B项正确。

完形填空

Of course, she wasn't really my aunt and, out of fear, I never called her that to her face. I only ____     to her as "My Aunt Fannie" because it always made my father chuckle and my mother look ____     at both of us—at me for being _____     of my elder and at my father for _____     my bad behavior. I ____     both reactions so I grasped every opportunity to work the name into as many conversations as possible.
As a young woman, my mother had worked in the _____      of a large Victorian farmhouse owned by Fannie Cratty and her twin brother, Farnsworth. They represented the ____     of the Cratty line. Neither had married ____     had any living heirs(继承人) and my father once told me in a whisper that it was because they were both too ____     to share their family wealth. During those years my mother helped Aunt Fanny make the best blueberry jam ever ____     by anyone in Glenfield. She was noted for her jam and for never ____     the recipe with anyone else. ____     my mother knew the recipe by heart, as long as Aunt Fannie was alive, she ____     made the jam without Ms. Cratty in our kitchen to direct the process and preserve the secret.
One year, after I had been particularly helpful with the jam process Aunt Fannie gave me a ____      and then made me promise that I would never spend it. " ____      this quarter," she said, "and some day you will be rich. I still have my very first quarter given by my grandfather." It had obviously ____     for her. So I followed her advice.
I now have the blueberry jam recipe and the quarter from Aunt Fannie. In people's eye Aunt Fannie's ____     was attributed to that secret recipe. But to me, it was just a ____     recipe. However, I keep them as ____     to hold firmly the valuable things in life. Money can make you feel rich for a while, but it is the relationships and the memories of time spent with friends and family that truly leave you wealthy. And that is a ____     that anyone can build.

C．delightedly

A．disappointed

B．disagreeable

C．disrespectful

D．dissatisfied

A．encouraging

C．Even though

A．regulations

B．reflections

单项选择题

一个有远大理想和坚强意志的人，任何困难和心理压力都难以被压服，这说明此人具有良好的( )。

A．生理因素
B．判断力
C．个性品质
D．价值观