A cylindrical rod of permanent-magnet alloy has radius and length
PHYSICS · Multi-part · Fermi University Physics · Electricity, Magnetism & Electromagnetism · Magnetic materials · Magnetic materials
Electricity, Magnetism and Electromagnetism, Ch Magnetisation, bound currents and the auxiliary field H
Problem
A cylindrical rod of permanent-magnet alloy has radius a=5.0mm and length 40cm. It is uniformly magnetised along its axis, M=Mz^ with M=6.4×105Am−1, where z^ points along the axis from the south end towards the north end. No free current flows anywhere. The rod is long enough compared with its radius that, well away from the ends, its interior may be treated as the interior of an infinitely long body.
((a)) Starting from Kb=M×n^, find the bound surface current per unit length on the curved side and state its direction in words; show also that each flat end carries none.
((b)) Find the total bound current that flows around a 1.0cm length of the curved side.
((c)) By identifying that surface current with the winding of a long solenoid, find the magnitude of B deep inside the rod, and then just outside the curved side.
((d)) Hence find the magnitude of H deep inside the rod.