Hello, I have an exam Tuesday and I'm solving the problems of previous years : 1. The problem statement, all variables and given/known data Consider a disk of radius a and length h of permanent magnetization M = Moz parallel to h. a/ what are the units of Mo ? b/Find the magnetic current density Jb inside the cylinder and the curface current density Kb on the three surfaces. c/ Write boundary conditions of B and H for the three surfaces. d/ Plot field lines for B and H everywhere. 2. Relevant equations Kb=Mxn^ Jb=∇xM 3. The attempt at a solution a/ A/m b. Inside the cylinder, the magnetization is constant so Jb=∇xM =0 I don't get what they mean by the three surfaces, inside the cylinder, outside and ? Thanks !