Abstract
In the literature a widely spread equation to correlate between the optical (σoptic) and electrical (σelec) conductivities in the form of (σelec=2λσoptα). Unfortunately, the tow sides of this equation have different dimensions i.e this equation is incorrect and the work by this equation must be stopped. The calculation of electrical/optical conductivity should be limited to the correct forms only deduced from the correct solution of Maxwell's equations.