Learning and teaching field, energy and potential concepts electromagnetism present special dfficulties to students and teachers. We inform on a study in domain. Comprehension of basic aspects related with those concepts attained by engineering students who had completed the course of electricity and magnetism is analysed. Results show the necessity of complementary qualitative and quantitative analysis in instruction. In traditional instruction qualitative treatments are usually delayed by treatments almost entirely centred in mathematics formalisms, whose physical mean is not clear for students.
