Suppose that two perpendicular mirrors bisect a given current distribution in such a way that both mirrors satisfy the mirror rule for that distribution. What does this imply about the magnetic field vector at points along the line where the mirrors intersect?
A) The magnetic field vectors must point along that line.
B) The magnetic field vectors must point halfway between the two planes perpendicular to that line.
C) The magnetic field is undefined along that line.
D) The magnetic field vectors must be zero along that line.
E) The supposed situation is impossible.

Question

Quizplus · Accepted Answer

The magnetic field vectors must be zero along the line where the mirrors intersect because the symmetry of the setup implies that any magnetic field component not along the line would be canceled out by its mirror image.

Suppose That Two Perpendicular Mirrors Bisect a Given Current Distribution