The surface effects on electric and magnetic variations arising from interfaces in three two‐dimensional conductivity models are compared in detail for four frequencies. It is found that the horizontal extent of the surface effects greatly depends on the dimensions of the different structures relative to the skin depths at the frequencies used. Also, a fundamentally important difference is revealed between H‐polarization and E‐polarization problems in that the apparent resistivity computed on the surface near the contact is discontinuous and changes abruptly in the H‐polarization case, whereas for E‐polarization the apparent resistivity is continuous and changes gradually across the contact.