题干

如图所示,电源电压保持不变,小灯泡的额定电压为12V,闭合开关S后,滑片P从最右端滑到最左端的过程中,小灯泡的I﹣U关系图象如图乙所示,下列说法中正确的是(  )

                    

A:电源电压为12V

B:滑动变阻器的最大阻值为9Ω

C:该电路总功率变化范围为12W~24W

D:小灯泡的额定功率为12W

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答案(点此获取答案解析)

A,B,C

同类题5

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    Anyone who has had a long-term illness knows that recovering at home can be lonely. This is can be especially true of children. They may feel isolated(孤立的)from their friends and classmates. Now, a small robot may help children who are recovering from a long-term illness in the hospital or at home. The robot takes their place at school. Through the robot, the children can hear their teachers and friends. They can also take part in classroom activities from wherever they are recovering – whether at home or from a hospital bed.

    The robot is called AV1.It is created by a company called “No Isolation”. AV1 goes to school for a child who is at home while recovering from a long-term illness. And the child's school friends must help. They carry the robot between classes and place the robot on the child's desk.

    Dolva, one co-funder (创始人)of No Isolation, explains how the robot AV1 works. She says, “the robot sits at the child's desk in the classroom and the child at home uses a tablet(平板电脑)or a phone to start it, control its movement with touch, and talk through it. So the robot becomes the eyes, the ears and the voice of the child at school.” The robot is equipped with speakers, microphones and cameras that make communicating easy. Moreover,The AVI was designed to be tough. It is water-resistant(防水) and can take a fall from a desk without damage. Inside AV1 is a small computer connected to a 4G network. AV1 is large and looks like a human for a reason. Dolva thinks this is important because the robot is expected to be a friend to the children.

    The robot just became available to the public. Hopefully AV1 will help some children feel less lonely while they are absent from class.