A thin metal strip carries conventional current toward the east while a uniform…
PHYSICS · Single correct · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism
Problem
A thin metal strip carries conventional current toward the east while a uniform magnetic field points vertically upward. A voltmeter connected across the north–south edges shows that the north edge is at a higher potential than the south edge. Which statement best explains what this observation reveals about the charge carriers in the strip?
(a) The dominant charge carriers are positive because the magnetic force drives them toward the north edge, raising its potential.
(b) The potential difference is due to a motional emf along the strip, so the sign of the charge carriers cannot be determined.
(c) The dominant charge carriers are negative because their magnetic deflection leaves the north edge electron-deficient.
(d) Because electrons move eastward with the current, their deflection toward the north edge makes that edge more negative and therefore at higher potential.