边长为L的正方形金属框在水平恒力F作用下，将穿过方向如图所示的_爱下问搜题

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问题选择题

边长为L的正方形金属框在水平恒力F作用下，将穿过方向如图所示的有界匀强磁场．磁场范围宽为d（d＞L）．已知线框进入磁场时恰好匀速．则线框进入磁场的过程和从另一侧出磁场的过程相比较，下列说法正确的是（）

A．线框中感应电流的方向相反

B．所受安培力的方向相反

C．出磁场过程产生的电能一定大于进磁场过程产生的电能

D．出磁场过程中任意时刻的电功率一定大于进磁场时的电功率

答案

AC

完形填空

Mr. Johnson lives outside the town. He works in a post office. His wife is often ill and six children __26____ at school. He works hard but he is often short of __27____. In the end of every month his family are always__28____.
One afternoon, on his way home, it suddenly began to __29____. When he got home, he was wet through. He hurried to go __30____ after supper and his wife washed the clothes and shoes for him. __31____ she went to bed, she brought the clothes into the room but __32____ the shoes. The next morning Mr. Johnson couldn’t find his shoes. His wife found a pair of __33____ shoes under the bed for him. Then he went to __34____ and told the policeman about it.
“I __35____ ten dollars for my shoes, sir,” said the man. “Look! I have to __36____ such a pair of worn-out shoes!”
Several days later the police __37____ a thief and found the shoes. They were as worn-out as the __38____ which Mr. Johnson was wearing.
“You’ve fooled us, Mr. Johnson,” said a policeman. “The shopkeeper told me a pair of new shoes like them __39____ only seven dollars!”
“You’re right, ,sir,” said Mr. Johnson. “I’ve __40____ them for five years and I had them mended six times. And I paid three dollars to the shoemaker for mending them!”

B．bus station

C．post office

D．police station

单项选择题

液压支架检修质量标准规定：构件平面上出现的凸起面积不得超（）cm²，高度不得超过（）mm。

A.90.10

B.100.10

C.100.20