A questionnaire about electromagnetic waves was submitted to 194 high school students after they completed the study of electromagnetism. The questionnaire consists of 6 multiple choice questions —each one with 5 options— also asking for a justification of the answer. They investigate the main conceptual issues and learning difficulties emerging from the literature about the time-dependent electromagnetic field. The answers’ analysis was carried out through an iterative categorization process, aimed at verifying the consistence between the selected options and the motivations provided by the participants. The results show which are the most common learning difficulties (e.g., the interpretation of the wave profile representation and the relationships between the velocity and the other quantities characterizing electromagnetic waves, such as frequency, intensity and the propagation medium) and how they are related to each other, providing implications for teaching.
D. et al. (Wed,) studied this question.