A.I=I1+I2 B.I=I1=I2 C.U=U1+U2 D.U=U1=U2
A.R=R1+R2 B.1/R=1/R1+1/R2 C.U=U1=U2 D.U=U1+U2
A.1/根號(hào)2 B.1/根號(hào)3 C.1/3