两个电阻R1=120欧,R2=100欧,串联后接入100伏的电路中,求R1的两端的电压和R2消耗的电功率.

问题描述:

两个电阻R1=120欧,R2=100欧,串联后接入100伏的电路中,求R1的两端的电压和R2消耗的电功率.

R1:R2=U1:U2
U1+U2=100
解出U1=600/11
P=U2²/R2
具体我就不算了

I=U/(R1+R2)=100/(120+100)=5/11=0.4545A
U1=IR1=(5/11)*120=54.55V
P2=I^2*R2=20.66W

串联,电流相等则:总电流I=U/R=100V/(120欧+100欧)=5/11A由于电流相等,则,通过R1、R2的电流均为5/11A由I=U/R得,U=IR,则R1的电压为:U1=I1R1=IR1=5/11A×120欧=54.55V有P=I^2R得,R2的电功率为:P2=I^2R2=(5/11A)^2×...

i = u / ( r1 + r2 ) = 100 / ( 120 + 100 ) = 5 / 11
u1 = i * r1 = ( 5 / 11 ) * 120 = 600 / 11
u2 = u - u1 = 100 - 600 / 11 = 500 / 11
p2 = u2 * i = ( 500 / 11 ) * ( 5 / 11 ) = 2500 / 121
如果要化成小数,就按按计算机好了~~