Question

2010北京市中考物理试题第22题

Answer 1

V1测量R1与滑动变阻器两端电器串联.

V2测量R2与滑动变阻器两端电压,

R1,R2和滑动变阻器串联,

当P位于A点时,

UR2-UR1=6V

当P位于B点时,U'R2-U'R1=3V

所以IA=2IB

[1]IA(R1+RA+R2)=IB(R1+RB+R2)

[2]U1/(RB+RA)=U2/(RA+R2)

[3]U1/(R1+RB)=U2(RB+R2)

把数据代入I1-I2=0.5A