9-5-4根据闭合电路欧姆定律E=U1+I1r=1.8+0.2rE=U2+I2r=1.6+0.4rr=1欧 E=2伏9-5-5根据闭合电路欧姆定律E=U1+U1r/R1=2.8+0.2rE=U2+I2r=2+ rr=1欧 E=3伏短路电流 I=E/r=3A开路电压 U=E=3V
