A:塑料袋
B:报纸
C:玻璃瓶
D:铝制饮料罐
如图所示,合上电键S1.当电键S2闭合时,电流表的示数为0.75A;当电键S2断开时,电流表的示数为0.5A,R1=R2=2Ω.求电源电动势E和内电阻r.
____ ____ ____ is willing to help me, I have to finish the task on my own.
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