A toroid has a square cross section with the length of an edge equal to the radius of the inner surface.The ratio of the magnitude of the magnetic field at the inner surface to the magnitude of the field at the outer surface is:
A)1/4
B)1/2
C)1
D)2
E)4

Question

Quizplus · Accepted Answer

The magnetic field inside a toroid is inversely proportional to the radius. Since the outer surface has a larger radius than the inner surface, the magnetic field at the inner surface is stronger. Given the square cross-section, the outer radius is twice the inner radius, making the field at the inner surface twice as strong as at the outer surface.

A Toroid Has a Square Cross Section with the Length