This study aims to explore problem-based learning (PBL) in conjunction with students' confidence in the basic ideas of electromagnetism and their motivational orientations and learning strategies. The 78 first-year geology and geophysics students followed a three-week PBL instruction in electromagnetism. The students' confidence was assessed through a diagnostic test on electromagnetism. The Motivated Strategies for Learning Questionnaire (MSLQ) was used to identify students' motivational orientations and learning strategies. The results indicate that many students were confident in incorrect answers, and had inadequate use of cognitive and metacognitive learning strategies. Providing students with some formative assessments during the PBL process could help them to better judge their understanding, which, in turn, would result in better student calibration (i.e., students would be more confident in their correct answers, and less confident in their incorrect answers) in electromagnetism. Helping the first-year PBL students to obtain effective cognitive and metacognitive learning strategies early in the academic year could improve their understanding of physics concepts. (Contains 3 tables.)