题干

将一电荷量为+Q的小球放在不带电的金属球附近,所形成的电场线分布如图所示,金属球表面的电势处处相等.a、b为电场中的两点,则(   )

A:a点的电场强度比b点的大

B:a点的电势比b点的高

C:检验电荷﹣q在a点的电势能比在b点的大

D:将检验电荷﹣q从a点移到b点的过程中,电场力做负功

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答案(点此获取答案解析)

A,B,D

同类题4

     I sat with my friend in a well-known coffee shop in a town of Italy.

  As we enjoyed our coffee, a man entered and sat beside us. He called the waiter over, saying, ”Two cups of coffee, one of them there on the1

    We heard his order with2 and noticed that he was served one cup of coffee 3he paid for two.

    When he left, the waiter put a piece of paper on the wall saying "A Cup of Coffee".

    While we were still there, two other men entered and 4three cups of coffee , two on the table and one on the wall. They had two but paid for 5 .  This time also, the waiter did the same thing.  It was  6  unusual for us.

    After a few days, we had a chance to enter this coffee shop again. While we were enjoying our coffee, a man  7  appeared homeless entered. He looked at the wall and said, "One cup of coffee from the wall."

    The waiter served a cup of coffee to this man with 8 The man had his coffee and left without    9  . We were amazed to watch all of this as the waiter   10 a piece of paper off the wall and threw it into the bin.

    Now it was no surprise for us---the matter was very 11  . The people of this town showed great respect for those people who needed help.

    Just think about   12this man wanted. He didn't have to lose his face to ask for a(n) 13  cup of coffee.   14 asking or knowing who was giving him this cup of coffee, he only looked at the wall, placed an order,  15 his coffee and left.

    It's a truly beautiful thing---probably the most beautiful wall anywhere in the world.