Detection of students' misconceptions regarding capacitance and resistance

Abstract

A questionnaire was constructed to assess how students analyze concepts about resistance and capacitance from their electricity and magnetism course. The questionnaire contained questions to assess how students perceive the relationship among: (1) capacitance C, potential difference V and charge Q in the equation C = Q/V, and (2) resistance R, voltage V and current I in the equation R = V/I.
Data show that around one-third of the respondents have the misconceptions of looking at: (1) capacitance as dependent on the charge of the capacitor's plates and the potential difference across the plates, and (2) resistance as dependent on the voltage across the resistor and the current along the resistor. The basis of the misconception was found to be the students' use of plain mathematical relationship of proportionality (or inverse proportionality) in analyzing the relationship among the physical quantities, and thus neglecting which physical quantity is constant and which is variable. It is suspected that the knowledge of the various values of capacitance and resistance made this misconception possible.