PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Two points, A and B, lie on the extension of the north-pole side of a small bar magnet that can be treated as an ideal magnetic dipole. Point A is located 4.0 cm from the center of the magnet along the dipole axis, while point B is located 12 cm from the center on the same line.
(a) Describe the direction of the magnetic field vectors at points A and B relative to the orientation of the magnet.
(b) Without performing numerical calculations, rank the magnitudes of the magnetic field at points A and B and justify your ranking using physical reasoning.
(c) A thin sheet of high-permeability material is inserted between the magnet and point B only, leaving the region around point A unchanged. Qualitatively describe how the field magnitude at point B is affected and explain your reasoning.