A circular coil rests on a horizontal table so that its area vector points straight upward
PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A circular coil rests on a horizontal table so that its area vector points straight upward. A uniform magnetic field of 0.40T is directed straight downward. Which of the following describes the sign of the magnetic flux through the coil and the physical reason for that sign?
(a) The flux is positive because the magnetic field is perpendicular to the plane of the coil.
(b) The flux is negative because the field is antiparallel to the coil’s area vector.
(c) The flux is positive because the field is parallel to the coil’s downward normal vector.
(d) The flux is negative because the field makes a 90∘ angle with the coil, so cos90∘=−1.