A numerical code for the electromagnetic analysis of high Tc superconductors by finite element method has been developed. The E-j characteristics of superconductors are represented with the n-value. The equivalent conductivity of superconductor is determined as a function of electric field, and Ohm's law is used as the constitutive equation. First, the current and magnetic flux distributions in the infinite slabs of superconductor exposed to a parallel external magnetic field are analyzed. The influence of n-value on Ac loss and the frequency dependence of Ac loss are studied. The AC loss in the infinitely-long superconductor tapes exposed to the external magnetic field is calculated numerically to study the influence of n-value.