如图所示，理想变压器原、副线圈的匝数比为10：1，b是原线圈的中心接头，电压表V和电流表A均为理想电表．从某时刻开始在原线圈c、d两端加上交变电压，其瞬时值表达式为u=220 sin100πt（V）．下列说法正确的是（ ）A．当单刀双掷开关与a连接时，电压表的示数为22 B．当单刀双掷开关与b连接时，电压表的示数为11V C．当单刀双掷开关与a连接，滑动变阻器触头P向上移动的过程中，电压表的示数不变，电流表的示数变大 D．单刀掷开关由a扳向b时（滑动变阻器触头P不动），电压表和电流表的示数均变大  |
答案：D
Hi Jenny, Thank you for 小题1: me to go shopping with you this week. I’d love to go, but I really 小题2: these days. You know I am a schoolgirl. I have to go to school 小题3: weekdays and every evening I must do my homework. And I am going to see my grandma this Saturday. I am going to look after 小题4: because she is ill in hospital. 小题5: I am free this Sunday, I have to babysit my little sister at home. She is very 小题6: . However, are you and your little brother free this Sunday? Can you come over to my home? You can 小题7: a taxi. It only takes you ten 小题8: to my home by taxi. Then we four can enjoy 小题9: games together(一起). The two little kids 小题10: so happy to stay together and play. Come on, I am waiting for you. Kate |
V