题目

在研究微型电动机的性能时,可采用图示的实验电路.当调节滑动变阻器R,使电动机停止转动时,电流表和电压表的示数分别为0.5 A和1.0 V;重新调节R,使电动机恢复正常运转时,电流表和电压表的示数分别为2.0 A和15.0 V.则有关这台电动机正常运转时的说法正确的是( )A.电动机的输出功率为8 WB.电动机的输出功率为30 WC.电动机的内电阻为2 ΩD.电动机的内电阻为7.5 Ω补全对话 根据对话内容用正确的句子完成对话 A: Good morning, Mr. Zhang. B: ___________(1), Mr. Wang. A: ____________(2), Mr. Zhang? B: I’m from Shanghai. ______________(3)? A: I’m from Xi’an. Are you a worker? B: Yes, I am. ___________________(4)? A: I’m a teacher. Do you work in a car factory? B: Yes, I do. ________________(5)? A: I teach English. B: How many children do you have? A: I have one. B: Do you have __________________(6)? A: I have a son. B: ____________________(7)? A: He’s a student. B: _________________(8)? A: He’s twelve. ___________________(9) any children? B: Yes. I have a daughter. She’s a student, too. A: ________________(10)? B: Yes. She likes English very much.