Question

如图所示,如果考虑电源的电阻,闭合开关,电源电阻消耗的功率为Pr,R1消耗功率为P1,R2消耗功率为P2,电路

Answer 1

P=E*I

Pr=I^2*r

P1=I1^2*R1=U*I1

P2=I2^2*R2=U*I2

I1+I2=I

E-I*r=U

E=I*r+U

Pr+P1+P2=I^2*r+U*I1+U*I2

=I^2*r+U*(I1+I2)

=I^2*r+U*I

=I*(I*r+U)

=E*I

=P

P=Pr+P1+P2