两电阻R1和R2接在各自电路中,当U1:U2=2:1,I1:I2=4:1时,两电阻R1、R2阻值之比等于( )A.1:2B.2:1C.8:1D.1:8答案:∵U1:U2=2:1,I1:I2=4:1,∴电阻R1和R2阻值之比为:R1R2=U1I1U2I2=U1I1×I2U2=2×11×4=12.故选A.来源:电商信息网