(1)根据电路图可知,R2、R3并联后与R1串联,接入电源,
根据闭合电路欧姆定律得:
I=
=E R总
=E
R1+r+
R2R3
R2+R3
=1A,3 0.8+0.2+
18 9
则路端电压U=E-Ir=3-1×0.2=2.8V
(2)电阻R2两端的电压U2=U-U1=2.8-1×0.8=2V
则电阻R2消耗的电功率P2=
=U2 R
=U22 R2
=1.33W4 3
答:(1)电流表的示数为1A,电压表读数为2.8V;
(2)电阻R2消耗的电功率为1.33W.