Force on steel ball near bar magnet · BPhO 2009 #7
Physics · electromagnetism
Problem
A dipole bar magnet is shown in the diagram below, along with the pattern of field lines around it. A small steel ball bearing is placed at point O shown. What force would act upon the ball bearing?
[Figure: Bar magnet with field lines and point O marked, with point X at center of magnet]
A. The ball bearing is in equilibrium and has no resultant force
B. The resultant force is along the field line, from north to south
C. The resultant force acts towards the centre point X of the magnet
D. The resultant force acts away from the centre point X of the magnet