R2消耗的功率为6W,R1=0.5 R2,若将他们并联后仍接在该电源上,则电路消耗的总功率为?(求详细过程)
答案:来40.5W解析:电源自电压为U,根据串联电路电压分配的特点,即:U1:U2=R1:R2=1:2即:U1=U/3 U2=2U/3且,R1的功率,P1=U1^2/R1=3 即,U^2/9R1=3,推导出:U^2/R1=27W并联时,电压均为U,功率之和为:P总=U^2/R1+U^2/R2=27+U^2/2R1=27×13.5=40.5W