EXACT ELECTRIC-MAGNETIC DUALITY IN N=2 SUPERSYMMETRIC QCD THEORIES

We analyze the Coulomb phase of theories of N = 2 SQCD with SU(N-c) ga uge groups which are conjectured to have exact electric-magnetic duali ty. We discuss the duality transformation of the particle spectrum, em phasizing the differences between the general case and the SU(2) case. Some difficulties associated with the definition of the duality trans formation for a general gauge group are discussed. We compute the clas sical monopole spectrum of these theories, and when it is possible we use it to check the consistency of the duality. Generally these theori es may have phase transitions between strong and weak coupling, which prevent the semi-classical computation from being useful for checking the duality.