Probing university students' understanding of electromotive force in electricity

Abstract

The goal of this study is to identify students' difficulties with learning the concepts of electromotive force (emf) and potential difference in the context of transitory currents and resistive direct-current circuits. To investigate these difficulties, we developed a questionnaire based on an analysis of the theoretical and epistemological framework of physics, which was then administered to first-year engineering and physics students at universities in Spain, Colombia, and Belgium. The results of the study show that student difficulties seem to be strongly linked to the absence of an analysis of the energy balance within the circuit and that most university students do not clearly understand the usefulness of and the difference between the concepts of potential difference and emf.

Introductory university physics students’ understanding of some key characteristics of classical theory of the electromagnetic field

“…Moreover, the Lorentz force exerted on the moving charge is ⃗ F ¼ q⃗ v × ⃗ B and so again with the right-hand rule the direction of the force is determined (vertically downward in the drawing)." (Magnetic Force question, UPV/EHU student 29). "The force is perpendicular to the field and the velocity.…”

“…The findings of this study contribute to the teaching of electromagnetism in the European countries where it has taken place (Spain, Belgium, and Ireland), but are also of international interest. Replication studies and planned cross-country studies, such as the research carried out by the authors on other subjects [29,30] and by other colleagues [31], suggest that, although there may be variations among individuals, there are common patterns of conceptual difficulties that appear in the group of students as a whole, regardless of differences in their educational system, and cultural background. These empirical studies are convergent with the psychological cognitive theory called phenomenography [32].…”

Investigating and improving introductory physics students’ understanding of electric field and the superposition principle: The case of a continuous charge distribution

“…Several prior studies by several groups have focused on the difficulties of introductory physics students with electricity and magnetism and strategies that may help students learn these concepts better [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. McDermott, Shaffer, and the Physics Education Group at University of Washington have performed investigations of the difficulties students have with learning introductory physics concepts and developed an inquiry-based curriculum on various topics, e.g., electrical circuits, that focuses on significantly reducing the difficulties [16][17][18].…”

“…Gladding et al have developed a smartPhysics suite focused on helping students learn electricity and magnetism [20]. Zuza et al have investigated student difficulties with Faraday's law and strategies to help students learn related concepts better [21][22]. Guruswamy et al [23] studied student understanding of transfer of charge between conductors, and Guisasola et al [24][25][26] have carried out investigations related to student understanding of capacitors.…”

Some didactical suggestions for a deeper embedding of DC circuits into electromagnetism

“…A source of widespread students' misunderstanding is the concept of the electromotive force (emf ) of a battery [17,18]. Although aware that this problem might distress only European students, our opinion is that much more care should be devoted to discuss this concept.…”