Abstract
Alfvén's theorem concerning "frozen-in magnetic field" states that the magnetic field lines, passing through an ideal conductive fluid, are frozen with the fluid, and the fluid can move along the magnetic field lines but cannot cross them. Here, we present two negative experimental results and an analysis of the theorem. The experimental results prove that Alfvén's theorem cannot correctly explain the evolution of the magnetic field and magnetic resistance; therefore, it is incorrect. Mathematical analysis explains why this theorem is incorrect.