It's kind of embarassing but I have almost finished a introductory EM class and I'm still not sure in a formal way in which cases the EMF is equal to the voltage. EMF was defined as the work done on a charge per unit of charge by any EM originated force when the charge would take a certain path. From here on I kind of forgot about the real definition of the voltage which was the integral of the electric field along that path and used EMF and voltage interchangable in any situation (Faraday induction and so on). It seems to have worked out until now but now that I look at the definitions of EMF and voltage it seems that some subtleties may arise in a more formal treatment. I would appreciate if someone who had the same confusion in their intro EM class could elaborate a bit. Thanks.