Maxwell Equations, Macroscopic Electromagnetism, Conservation Laws — John David Jackson
Physics — E&M · loop-near-permeable-slab-force
Problem
A circular loop of wire having a radius a and carrying a current I is located in vacuum with its center a distance d away from a semi-infinite slab of permeability μ. Find the force acting on the loop when
(a) the plane of the loop is parallel to the face of the slab,
(b) the plane of the loop is perpendicular to the face of the slab.
(c) Determine the limiting form of your answer to parts a and b when d≫a. Can you obtain these limiting values in some simple and direct way?