A.C=1 B.C =2 C.C =3 D.C =4
A.5T/3V B.-2T/5V C.5V/3T D.-7T/5V
A.μ>0,△S<0 B.μ<0,△S>0 C.μ不一定,△S>0 D.μ不一定,△S<0