Question

R1=30欧,当开关S闭合后,滑动变阻器的滑片P在B端时,电压表的示数为4.5伏;滑片在中

Answer 1

1)E=(U1/R2)*(R1+R2)=(U2/R2*2)*(R1+R2/2)

R2=R1=30Ω

2)E=(U1/R2)*(R1+R2)=9V

A.Ia=E/R1=0.3A

B.Ib=E/(R1+R2)=0.15A

C.Ic=E/(R1+R2/2)=0.2A