如图所示,电源电压保持不变,灯泡L2的电阻R2=5Ω,闭合开关,如果电流表A1的读数为1.0A,电流表A2的读数是0.6A,求(1)电源电压 (2)通过灯L1的电流(3)L1的电阻值
3V 0.4A 7.5Ω
【解析】(1)电源电压为:
(2)根据并联电路的电流规律知,通过灯L1的电流为:
(3),得L1的电阻值为: 答案:10.听第7段材料,回答第8至10题.8.What relation is Ms Leska to the woman?A.Her roommate.B.Her cousin.C.Her workmate.9.Who will probably meet Kevin at the bus station?A.Claudia.B.Tara.C.Albee.10.What will the woman do at 3:00 p.m.?A.Meet the man.B.Look after Ms Leska.C.Teach a class.