如图所示，绕在铁芯上的线圈与电源、滑动变阻器和电键组成闭合回_爱下问搜题

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问题不定项选择

如图所示，绕在铁芯上的线圈与电源、滑动变阻器和电键组成闭合回路，在铁芯的右端套有一个表面绝缘的铜环A，下列各种情况中铜环A中有感应电流的是

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A、线圈中通以恒定的电流　　

B、通电时，使变阻器的滑片P作匀速移动　　

C、通电时，使变阻器的滑片P作加速移动　　

D、将电键突然断开的瞬间

答案

BCD

填空题

选词填空并注意其适当形式。（10分）

all the time , a piece of , be good at , how about, have a conversation,
have a good time , in the north of, lots of, matter, against

小题1:They ___________________in the park last week.
小题2:Daming is a good student. He ____________all kinds of things in the life.
小题3:Don’t smoke in the school, It is ________ the rule of the school.
小题4:His sister was angry with him, so she was crying __________in the bedroom.
小题5:Now let’s ________________to talk about the sports meeting next week.
小题6:The weather gets cooler and cooler, _________ wearing warm clothes?
小题7:The Mid autumn Day is coming , My mother bought ________meat for us.
小题8:_____________ China has many beautiful places.
小题9:She looked very unhappy yesterday. What was the ________ with her?
小题10:He is very thirsty,so he drinks____________milk.

填空题

的值是常数2，则a的取值范围是______．