∵R1、R2串联∴各处的电流相等;U1:U2=IR1:IR2=R1:R2=5Ω:10Ω=1:2;P1:P2=I2R1:I2R2=R1:R2=5Ω:10Ω=1:2;∵R1、R2串联∴各支路两端的电压相等;I1?:I2?= U R1 : U R2 =R2:R1=10Ω:5Ω=2:1;P1?:P2?= U2 R1 : U2 R2 =R2:R1=10Ω:5Ω=2:1.故答案为:1:2,1:2,2:1,2:1.